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8
windows/security/threat-protection/security-policy-settings/TOC.yml
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@ -136,10 +136,6 @@
href: interactive-logon-smart-card-removal-behavior.md
- name: "Microsoft network client: Digitally sign communications (always)"
href: microsoft-network-client-digitally-sign-communications-always.md
- name: "SMBv1 Microsoft network client: Digitally sign communications (always)"
href: smbv1-microsoft-network-client-digitally-sign-communications-always.md
- name: "SMBv1 Microsoft network client: Digitally sign communications (if server agrees)"
href: smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md
- name: "Microsoft network client: Send unencrypted password to third-party SMB servers"
href: microsoft-network-client-send-unencrypted-password-to-third-party-smb-servers.md
- name: "Microsoft network server: Amount of idle time required before suspending session"
@ -148,10 +144,6 @@
href: microsoft-network-server-attempt-s4u2self-to-obtain-claim-information.md
- name: "Microsoft network server: Digitally sign communications (always)"
href: microsoft-network-server-digitally-sign-communications-always.md
- name: "SMBv1 Microsoft network server: Digitally sign communications (always)"
href: smbv1-microsoft-network-server-digitally-sign-communications-always.md
- name: "SMBv1 Microsoft network server: Digitally sign communications (if client agrees)"
href: smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md
- name: "Microsoft network server: Disconnect clients when logon hours expire"
href: microsoft-network-server-disconnect-clients-when-logon-hours-expire.md
- name: "Microsoft network server: Server SPN target name validation level"

60
windows/security/threat-protection/security-policy-settings/microsoft-network-client-digitally-sign-communications-always.md
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@ -1,17 +1,13 @@
---
title: Microsoft network client Digitally sign communications (always) (Windows 10)
title: Microsoft network client Digitally sign communications (always)
description: Best practices and security considerations for the Microsoft network client Digitally sign communications (always) security policy setting.
ms.assetid: 4b7b0298-b130-40f8-960d-60418ba85f76
ms.reviewer:
manager: aaroncz
ms.author: vinpa
ms.prod: windows-client
ms.mktglfcycl: deploy
ms.sitesec: library
ms.pagetype: security
ms.localizationpriority: medium
author: vinaypamnani-msft
ms.date: 06/28/2018
ms.date: 01/13/2023
ms.technology: itpro-security
ms.topic: conceptual
---
@ -19,12 +15,26 @@ ms.topic: conceptual
# Microsoft network client: Digitally sign communications (always)
**Applies to**
- Windows 11
- Windows 10
- Windows Server
- Windows 11
- Windows 10
- Windows Server
This article describes the best practices, location, values, policy management, and security considerations for the **Microsoft network client: Digitally sign communications (always)** security policy setting for SMBv3 and SMBv2.
> [!NOTE]
> This article is about the server message block (SMB) v2 and v3 protocols. SMBv1 isn't secure and has been deprecated in Windows. Starting with Windows 10, version 1709, and Windows Server, version 1709, [SMBv1 isn't installed by default](/windows-server/storage/file-server/troubleshoot/smbv1-not-installed-by-default-in-windows).
> [!IMPORTANT]
> Microsoft doesn't recommend using the following group policy settings:
>
> - **Microsoft network server: Digitally sign communications (if client agrees)**
> - **Microsoft network client: Digitally sign communications (if server agrees)**
>
> Also don't use the **EnableSecuritySignature** registry settings.
>
> These options only affect the SMBv1 behavior. They can be effectively replaced by the **Digitally sign communications (always)** group policy setting or the **RequireSecuritySignature** registry setting.
## Reference
The Server Message Block (SMB) protocol provides the basis for file and print sharing and many other networking operations, such as remote Windows administration. To prevent "man-in-the-middle" attacks that modify SMB packets in transit, the SMB protocol supports digital signing of SMB packets.
@ -35,22 +45,21 @@ Beginning with SMBv2 clients and servers, signing can be either *required* or *n
Negotiation occurs between the SMB client and the SMB server to decide whether signing will be used. The following table shows the effective behavior for SMBv3 and SMBv2.
| | Server – required | Server – not required |
| Client | Server - required | Server - not required |
|---------------------------|---------------------|------------------------|
| **Client – required** | Signed | Signed |
| **Client – not required** | Signed <sup>1</sup> | Not signed<sup>2</sup> |
| **Client - required** | Signed | Signed |
| **Client - not required** | Signed <sup>1</sup> | Not signed<sup>2</sup> |
</br>
<sup>1</sup> Default for domain controller SMB traffic</br>
<sup>2</sup> Default for all other SMB traffic
Performance of SMB signing is improved in SMBv2. For more information, see [Potential impact](#potential-impact).
Performance of SMB signing is improved in SMBv2. For more information, see [Potential effect](#potential-effect).
### Possible values
- Enabled
- Disabled
- Enabled
- Disabled
### Best practice
@ -62,16 +71,16 @@ Enable **Microsoft network client: Digitally sign communications (always)**.
### Default values
The following table lists the default values for this policy. Default values are also listed on the policy’s property page.
The following table lists the default values for this policy. Default values are also listed on the policy's property page.
| Server type or GPO | Default value |
| - | - |
| Default Domain Policy| Disabled|
| Default Domain Controller Policy | Disabled|
| Stand-Alone Server Default Settings | Disabled|
| DC Effective Default Settings | Disabled|
| Member Server Effective Default Settings | Disabled|
| Client Computer Effective Default Settings | Disabled|
| Default Domain Policy| Disabled|
| Default Domain Controller Policy | Disabled|
| Stand-Alone Server Default Settings | Disabled|
| DC Effective Default Settings | Disabled|
| Member Server Effective Default Settings | Disabled|
| Client Computer Effective Default Settings | Disabled|
## Policy management
@ -98,10 +107,11 @@ Enable **Microsoft network client: Digitally sign communications (always)**.
> [!NOTE]
> An alternative countermeasure that could protect all network traffic is to implement digital signatures through IPsec. There are hardware-based accelerators for IPsec encryption and signing that can be used to minimize the performance impact on servers. No such accelerators are available for SMB signing.
### Potential impact
### Potential effect
Storage speeds affect performance. A faster drive on the source and destination allows more throughput, which causes more CPU usage for signing. If you're using a 1-Gb Ethernet network or slower storage speed with a modern CPU, there's limited degradation in performance. If you're using a faster network (such as 10 Gb), the performance impact of signing may be greater.
## Related topics
## Related articles
- [Security options](security-options.md)
- [Microsoft network server: Digitally sign communications (always)](microsoft-network-server-digitally-sign-communications-always.md)

76
windows/security/threat-protection/security-policy-settings/microsoft-network-server-digitally-sign-communications-always.md
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@ -1,33 +1,43 @@
---
title: Microsoft network server Digitally sign communications (always) (Windows 10)
title: Microsoft network server Digitally sign communications (always)
description: Best practices, security considerations, and more for the security policy setting, Microsoft network server Digitally sign communications (always).
ms.assetid: 2007b622-7bc2-44e8-9cf1-d34b62117ea8
ms.reviewer:
ms.author: vinpa
ms.prod: windows-client
ms.mktglfcycl: deploy
ms.sitesec: library
ms.pagetype: security
ms.localizationpriority: medium
author: vinaypamnani-msft
ms.author: vinpa
ms.reviewer:
manager: aaroncz
audience: ITPro
ms.topic: conceptual
ms.date: 06/21/2018
ms.prod: windows-client
ms.technology: itpro-security
ms.localizationpriority: medium
ms.topic: conceptual
ms.date: 01/13/2023
---
# Microsoft network server: Digitally sign communications (always)
**Applies to**
- Windows 10
- Windows Server
- Windows 11
- Windows 10
- Windows Server
Describes the best practices, location, values, policy management and security considerations for the **Microsoft network server: Digitally sign communications (always)** security policy setting for SMBv3 and SMBv2.
> [!NOTE]
> This article is about the server message block (SMB) v2 and v3 protocols. SMBv1 isn't secure and has been deprecated in Windows. Starting with Windows 10, version 1709, and Windows Server, version 1709, [SMBv1 isn't installed by default](/windows-server/storage/file-server/troubleshoot/smbv1-not-installed-by-default-in-windows).
> [!IMPORTANT]
> Microsoft doesn't recommend using the following group policy settings:
>
> - **Microsoft network server: Digitally sign communications (if client agrees)**
> - **Microsoft network client: Digitally sign communications (if server agrees)**
>
> Also don't use the **EnableSecuritySignature** registry settings.
>
> These options only affect the SMBv1 behavior. They can be effectively replaced by the **Digitally sign communications (always)** group policy setting or the **RequireSecuritySignature** registry setting.
## Reference
The Server Message Block (SMB) protocol provides the basis for file and print sharing and many other networking operations, such as remote Windows administration. To prevent man-in-the-middle attacks that modify SMB packets in transit, the SMB protocol supports the digital signing of SMB packets.
The Server Message Block (SMB) protocol provides the basis for file and print sharing and many other networking operations, such as remote Windows administration. To prevent man-in-the-middle attacks that modify SMB packets in transit, the SMB protocol supports the digital signing of SMB packets.
Implementation of digital signatures in high-security networks helps prevent the impersonation of client computers and servers, which is known as "session hijacking." But misuse of these policy settings can cause data access failure.
@ -35,22 +45,21 @@ Beginning with SMBv2 clients and servers, signing can be either required or not
There's a negotiation done between the SMB client and the SMB server to decide whether signing will effectively be used. The following table has the effective behavior for SMBv3 and SMBv2.
| | Server – Required | Server – Not Required |
| Client | Server - Required | Server - Not Required |
|---------------------------|---------------------|------------------------|
| **Client – Required** | Signed | Signed |
| **Client – Not Required** | Signed <sup>1</sup> | Not Signed<sup>2</sup> |
| **Client - Required** | Signed | Signed |
| **Client - Not Required** | Signed <sup>1</sup> | Not Signed<sup>2</sup> |
</br>
<sup>1</sup> Default for domain controller SMB traffic</br>
<sup>2</sup> Default for all other SMB traffic
Performance of SMB signing is improved in SMBv2. For more information, see [Potential impact](#potential-impact).
Performance of SMB signing is improved in SMBv2. For more information, see [Potential effect](#potential-effect).
### Possible values
- Enabled
- Disabled
- Enabled
- Disabled
### Best practices
@ -58,20 +67,20 @@ Enable **Microsoft network server: Digitally sign communications (always)**.
### Location
Computer Configuration\\Windows Settings\\Security Settings\\Local Policies\\Security Options
*Computer Configuration\\Windows Settings\\Security Settings\\Local Policies\\Security Options*
### Default values
The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.
The following table lists the actual and effective default values for this policy. Default values are also listed on the policy's property page.
| Server type or GPO | Default value |
| - | - |
| Default Domain Policy| Disabled|
| Default Domain Controller Policy | Enabled|
| Stand-Alone Server Default Settings | Disabled|
| DC Effective Default Settings | Enabled|
| Member Server Effective Default Settings| Disabled|
| Client Computer Effective Default Settings | Disabled|
| Default Domain Controller Policy | Enabled|
| Stand-Alone Server Default Settings | Disabled|
| DC Effective Default Settings | Enabled|
| Member Server Effective Default Settings| Disabled|
| Client Computer Effective Default Settings | Disabled|
## Policy management
@ -95,13 +104,14 @@ SMB is the resource-sharing protocol that is supported by many Windows operating
Enable **Microsoft network server: Digitally sign communications (always)**.
>[!NOTE]
>An alternative countermeasure that could protect all network traffic is to implement digital signatures with IPsec. There are hardware-based accelerators for IPsec encryption and signing that could be used to minimize the performance impact on the servers' CPUs. No such accelerators are available for SMB signing.
> [!NOTE]
> An alternative countermeasure that could protect all network traffic is to implement digital signatures with IPsec. There are hardware-based accelerators for IPsec encryption and signing that could be used to minimize the performance impact on the servers' CPUs. No such accelerators are available for SMB signing.
### Potential impact
### Potential effect
Storage speeds impact performance. A faster drive on the source and destination allows more throughput, which causes more CPU usage of signing. If you're using a 1-GB Ethernet network or slower storage speed with a modern CPU, there's limited degradation in performance. If you're using a faster network (such as 10 Gb), the performance impact of signing may be greater.
## Related topics
## Related articles
- [Security Options](security-options.md)
- [Microsoft network client: Digitally sign communications (always)](microsoft-network-client-digitally-sign-communications-always.md)

73
windows/security/threat-protection/security-policy-settings/security-options.md
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@ -1,17 +1,13 @@
---
title: Security Options (Windows 10)
title: Security options
description: Introduction to the Security Options settings of the local security policies plus links to more information.
ms.assetid: 405ea253-8116-4e57-b08e-14a8dcdca92b
ms.reviewer:
manager: aaroncz
ms.author: vinpa
ms.prod: windows-client
ms.mktglfcycl: deploy
ms.sitesec: library
ms.pagetype: security
ms.localizationpriority: medium
author: vinaypamnani-msft
ms.date: 06/28/2018
ms.date: 01/13/2023
ms.technology: itpro-security
ms.topic: conceptual
---
@ -19,8 +15,9 @@ ms.topic: conceptual
# Security Options
**Applies to**
- Windows 11
- Windows 10
- Windows 11
- Windows 10
Provides an introduction to the **Security Options** settings for local security policies and links to more information.
@ -34,75 +31,71 @@ For info about setting security policies, see [Configure security policy setting
| Article | Description |
| - | - |
| [Accounts: Administrator account status](accounts-administrator-account-status.md) | Describes the best practices, location, values, and security considerations for the **Accounts: Administrator account status** security policy setting.|
| [Accounts: Block Microsoft accounts](accounts-block-microsoft-accounts.md) | Describes the best practices, location, values, management, and security considerations for the **Accounts: Block Microsoft accounts** security policy setting.|
| [Accounts: Guest account status](accounts-guest-account-status.md) | Describes the best practices, location, values, and security considerations for the **Accounts: Guest account status** security policy setting.|
| [Accounts: Administrator account status](accounts-administrator-account-status.md) | Describes the best practices, location, values, and security considerations for the **Accounts: Administrator account status** security policy setting.|
| [Accounts: Block Microsoft accounts](accounts-block-microsoft-accounts.md) | Describes the best practices, location, values, management, and security considerations for the **Accounts: Block Microsoft accounts** security policy setting.|
| [Accounts: Guest account status](accounts-guest-account-status.md) | Describes the best practices, location, values, and security considerations for the **Accounts: Guest account status** security policy setting.|
| [Accounts: Limit local account use of blank passwords to console logon only](accounts-limit-local-account-use-of-blank-passwords-to-console-logon-only.md) | Describes the best practices, location, values, and security considerations for the **Accounts: Limit local account use of blank passwords to console logon only** security policy setting. |
| [Accounts: Rename administrator account](accounts-rename-administrator-account.md)| This security policy article for the IT professional describes the best practices, location, values, and security considerations for this policy setting.|
| [Accounts: Rename guest account](accounts-rename-guest-account.md) | Describes the best practices, location, values, and security considerations for the **Accounts: Rename guest account** security policy setting.|
| [Audit: Audit the access of global system objects](audit-audit-the-access-of-global-system-objects.md) | Describes the best practices, location, values, and security considerations for the **Audit: Audit the access of global system objects** security policy setting.|
| [Audit: Audit the use of Backup and Restore privilege](audit-audit-the-use-of-backup-and-restore-privilege.md) | Describes the best practices, location, values, and security considerations for the **Audit: Audit the use of Backup and Restore privilege** security policy setting.|
| [Accounts: Rename administrator account](accounts-rename-administrator-account.md)| This security policy article for the IT professional describes the best practices, location, values, and security considerations for this policy setting.|
| [Accounts: Rename guest account](accounts-rename-guest-account.md) | Describes the best practices, location, values, and security considerations for the **Accounts: Rename guest account** security policy setting.|
| [Audit: Audit the access of global system objects](audit-audit-the-access-of-global-system-objects.md) | Describes the best practices, location, values, and security considerations for the **Audit: Audit the access of global system objects** security policy setting.|
| [Audit: Audit the use of Backup and Restore privilege](audit-audit-the-use-of-backup-and-restore-privilege.md) | Describes the best practices, location, values, and security considerations for the **Audit: Audit the use of Backup and Restore privilege** security policy setting.|
| [Audit: Force audit policy subcategory settings (Windows Vista or later) to override audit policy category settings](audit-force-audit-policy-subcategory-settings-to-override.md) | Describes the best practices, location, values, and security considerations for the **Audit: Force audit policy subcategory settings (Windows Vista or later) to override audit policy category settings** security policy setting. |
| [Audit: Shut down system immediately if unable to log security audits](audit-shut-down-system-immediately-if-unable-to-log-security-audits.md)| Describes the best practices, location, values, management practices, and security considerations for the **Audit: Shut down system immediately if unable to log security audits** security policy setting. |
| [DCOM: Machine Access Restrictions in Security Descriptor Definition Language (SDDL) syntax](dcom-machine-access-restrictions-in-security-descriptor-definition-language-sddl-syntax.md)| Describes the best practices, location, values, and security considerations for the **DCOM: Machine Access Restrictions in Security Descriptor Definition Language (SDDL) syntax** policy setting. |
| [DCOM: Machine Launch Restrictions in Security Descriptor Definition Language (SDDL) syntax](dcom-machine-launch-restrictions-in-security-descriptor-definition-language-sddl-syntax.md)| Describes the best practices, location, values, and security considerations for the **DCOM: Machine Launch Restrictions in Security Descriptor Definition Language (SDDL) syntax** security policy setting. |
| [Devices: Allow undock without having to log on](devices-allow-undock-without-having-to-log-on.md)| Describes the best practices, location, values, and security considerations for the **Devices: Allow undock without having to log on** security policy setting.|
| [Devices: Allowed to format and eject removable media](devices-allowed-to-format-and-eject-removable-media.md) | Describes the best practices, location, values, and security considerations for the **Devices: Allowed to format and eject removable media** security policy setting.|
| [Devices: Prevent users from installing printer drivers](devices-prevent-users-from-installing-printer-drivers.md) | Describes the best practices, location, values, and security considerations for the **Devices: Prevent users from installing printer drivers** security policy setting.|
| [Devices: Allow undock without having to log on](devices-allow-undock-without-having-to-log-on.md)| Describes the best practices, location, values, and security considerations for the **Devices: Allow undock without having to log on** security policy setting.|
| [Devices: Allowed to format and eject removable media](devices-allowed-to-format-and-eject-removable-media.md) | Describes the best practices, location, values, and security considerations for the **Devices: Allowed to format and eject removable media** security policy setting.|
| [Devices: Prevent users from installing printer drivers](devices-prevent-users-from-installing-printer-drivers.md) | Describes the best practices, location, values, and security considerations for the **Devices: Prevent users from installing printer drivers** security policy setting.|
| [Devices: Restrict CD-ROM access to locally logged-on user only](devices-restrict-cd-rom-access-to-locally-logged-on-user-only.md) | Describes the best practices, location, values, and security considerations for the **Devices: Restrict CD-ROM access to locally logged-on user only** security policy setting. |
| [Devices: Restrict floppy access to locally logged-on user only](devices-restrict-floppy-access-to-locally-logged-on-user-only.md)| Describes the best practices, location, values, and security considerations for the **Devices: Restrict floppy access to locally logged-on user only** security policy setting. |
| [Domain controller: Allow server operators to schedule tasks](domain-controller-allow-server-operators-to-schedule-tasks.md)| Describes the best practices, location, values, and security considerations for the **Domain controller: Allow server operators to schedule tasks** security policy setting. |
| [Domain controller: LDAP server signing requirements](domain-controller-ldap-server-signing-requirements.md)| Describes the best practices, location, values, and security considerations for the **Domain controller: LDAP server signing requirements** security policy setting. |
| [Domain controller: Refuse machine account password changes](domain-controller-refuse-machine-account-password-changes.md) | Describes the best practices, location, values, and security considerations for the **Domain controller: Refuse machine account password changes** security policy setting.|
| [Domain controller: Refuse machine account password changes](domain-controller-refuse-machine-account-password-changes.md) | Describes the best practices, location, values, and security considerations for the **Domain controller: Refuse machine account password changes** security policy setting.|
| [Domain member: Digitally encrypt or sign secure channel data (always)](domain-member-digitally-encrypt-or-sign-secure-channel-data-always.md) | Describes the best practices, location, values, and security considerations for the **Domain member: Digitally encrypt or sign secure channel data (always)** security policy setting. |
| [Domain member: Digitally encrypt secure channel data (when possible)](domain-member-digitally-encrypt-secure-channel-data-when-possible.md)| Describes the best practices, location, values, and security considerations for the **Domain member: Digitally encrypt secure channel data (when possible)** security policy setting. |
| [Domain member: Digitally sign secure channel data (when possible)](domain-member-digitally-sign-secure-channel-data-when-possible.md)| Describes the best practices, location, values, and security considerations for the **Domain member: Digitally sign secure channel data (when possible)** security policy setting.|
| [Domain member: Disable machine account password changes](domain-member-disable-machine-account-password-changes.md)| Describes the best practices, location, values, and security considerations for the **Domain member: Disable machine account password changes** security policy setting.
| [Domain member: Digitally sign secure channel data (when possible)](domain-member-digitally-sign-secure-channel-data-when-possible.md)| Describes the best practices, location, values, and security considerations for the **Domain member: Digitally sign secure channel data (when possible)** security policy setting.|
| [Domain member: Disable machine account password changes](domain-member-disable-machine-account-password-changes.md)| Describes the best practices, location, values, and security considerations for the **Domain member: Disable machine account password changes** security policy setting.|
| [Domain member: Maximum machine account password age](domain-member-maximum-machine-account-password-age.md) |Describes the best practices, location, values, and security considerations for the **Domain member: Maximum machine account password age** security policy setting.|
|[Domain member: Require strong (Windows 2000 or later) session key](domain-member-require-strong-windows-2000-or-later-session-key.md)| Describes the best practices, location, values, and security considerations for the **Domain member: Require strong (Windows 2000 or later) session key** security policy setting. |
| [Interactive logon: Display user information when the session is locked](interactive-logon-display-user-information-when-the-session-is-locked.md)| Describes the best practices, location, values, and security considerations for the **Interactive logon: Display user information when the session is locked** security policy setting. |
| [Interactive logon: Don't display last signed-in](interactive-logon-do-not-display-last-user-name.md)| Describes the best practices, location, values, and security considerations for the **Interactive logon: Don't display last signed-in** security policy setting.|
| [Interactive logon: Don't display username at sign-in](interactive-logon-dont-display-username-at-sign-in.md)| Describes the best practices, location, values, and security considerations for the **Interactive logon: Do not display username at sign-in** security policy setting.|
| [Interactive logon: Do not require CTRL+ALT+DEL](interactive-logon-do-not-require-ctrl-alt-del.md)| Describes the best practices, location, values, and security considerations for the **Interactive logon: Do not require CTRL+ALT+DEL** security policy setting.|
| [Interactive logon: Machine account lockout threshold](interactive-logon-machine-account-lockout-threshold.md) | Describes the best practices, location, values, management, and security considerations for the **Interactive logon: Machine account lockout threshold** security policy setting.|
| [Interactive logon: Machine inactivity limit](interactive-logon-machine-inactivity-limit.md)| Describes the best practices, location, values, management, and security considerations for the **Interactive logon: Machine inactivity limit** security policy setting.|
| [Interactive logon: Don't display last signed-in](interactive-logon-do-not-display-last-user-name.md)| Describes the best practices, location, values, and security considerations for the **Interactive logon: Don't display last signed-in** security policy setting.|
| [Interactive logon: Don't display username at sign-in](interactive-logon-dont-display-username-at-sign-in.md)| Describes the best practices, location, values, and security considerations for the **Interactive logon: Do not display username at sign-in** security policy setting.|
| [Interactive logon: Do not require CTRL+ALT+DEL](interactive-logon-do-not-require-ctrl-alt-del.md)| Describes the best practices, location, values, and security considerations for the **Interactive logon: Do not require CTRL+ALT+DEL** security policy setting.|
| [Interactive logon: Machine account lockout threshold](interactive-logon-machine-account-lockout-threshold.md) | Describes the best practices, location, values, management, and security considerations for the **Interactive logon: Machine account lockout threshold** security policy setting.|
| [Interactive logon: Machine inactivity limit](interactive-logon-machine-inactivity-limit.md)| Describes the best practices, location, values, management, and security considerations for the **Interactive logon: Machine inactivity limit** security policy setting.|
| [Interactive logon: Message text for users attempting to log on](interactive-logon-message-text-for-users-attempting-to-log-on.md) | Describes the best practices, location, values, management, and security considerations for the **Interactive logon: Message text for users attempting to log on** security policy setting. |
| [Interactive logon: Message title for users attempting to log on](interactive-logon-message-title-for-users-attempting-to-log-on.md)| Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Message title for users attempting to log on** security policy setting. |
| [Interactive logon: Number of previous logons to cache (in case domain controller is not available)](interactive-logon-number-of-previous-logons-to-cache-in-case-domain-controller-is-not-available.md)| Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Number of previous logons to cache (in case domain controller is not available)** security policy setting. |
| [Interactive logon: Prompt user to change password before expiration](interactive-logon-prompt-user-to-change-password-before-expiration.md)| Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Prompt user to change password before expiration** security policy setting. |
| [Interactive logon: Require Domain Controller authentication to unlock workstation](interactive-logon-require-domain-controller-authentication-to-unlock-workstation.md)| Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Require Domain Controller authentication to unlock workstation** security policy setting. |
| [Interactive logon: Require smart card](interactive-logon-require-smart-card.md) | Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Require smart card** security policy setting.|
| [Interactive logon: Smart card removal behavior](interactive-logon-smart-card-removal-behavior.md) | Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Smart card removal behavior** security policy setting.|
| [Interactive logon: Require Windows Hello for Business or smart card](interactive-logon-require-smart-card.md) | Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Require Windows Hello for Business or smart card** security policy setting.|
| [Interactive logon: Smart card removal behavior](interactive-logon-smart-card-removal-behavior.md) | Describes the best practices, location, values, policy management, and security considerations for the **Interactive logon: Smart card removal behavior** security policy setting.|
| [Microsoft network client: Digitally sign communications (always)](microsoft-network-client-digitally-sign-communications-always.md) | Describes the best practices, location, values, policy management, and security considerations for the **Microsoft network client: Digitally sign communications (always)** security policy setting for SMBv3 and SMBv2. |
| [SMBv1 Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md) | Describes the best practices, location, values, policy management, and security considerations for the **Microsoft network client: Digitally sign communications (always)** security policy setting for SMBv1 only. |
| [SMBv1 Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md)| Describes the best practices, location, values, and security considerations for the **Microsoft network client: Digitally sign communications (if server agrees)** security policy setting for SMBv1 only. |
| [Microsoft network client: Send unencrypted password to third-party SMB servers](microsoft-network-client-send-unencrypted-password-to-third-party-smb-servers.md)| Describes the best practices, location, values, policy management, and security considerations for the **Microsoft network client: Send unencrypted password to third-party SMB servers** security policy setting. |
| [Microsoft network server: Amount of idle time required before suspending session](microsoft-network-server-amount-of-idle-time-required-before-suspending-session.md)| Describes the best practices, location, values, and security considerations for the **Microsoft network server: Amount of idle time required before suspending session** security policy setting. |
| [Microsoft network server: Attempt S4U2Self to obtain claim information](microsoft-network-server-attempt-s4u2self-to-obtain-claim-information.md)| Describes the best practices, location, values, management, and security considerations for the **Microsoft network server: Attempt S4U2Self to obtain claim information** security policy setting. |
| [Microsoft network server: Digitally sign communications (always)](microsoft-network-server-digitally-sign-communications-always.md)| Describes the best practices, location, values, policy management, and security considerations for the **Microsoft network server: Digitally sign communications (always)** security policy setting for SMBv3 and SMBv2.|
| [SMBv1 Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md)| Describes the best practices, location, values, policy management, and security considerations for the **Microsoft network server: Digitally sign communications (always)** security policy setting for SMBv1 only.|
| [SMBv1 Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md)| Describes the best practices, location, values, policy management, and security considerations for the **Microsoft network server: Digitally sign communications (if client agrees)** security policy setting for SMBv1 only. |
| [Microsoft network server: Digitally sign communications (always)](microsoft-network-server-digitally-sign-communications-always.md)| Describes the best practices, location, values, policy management, and security considerations for the **Microsoft network server: Digitally sign communications (always)** security policy setting for SMBv3 and SMBv2.|
| [Microsoft network server: Disconnect clients when logon hours expire](microsoft-network-server-disconnect-clients-when-logon-hours-expire.md)| Describes the best practices, location, values, and security considerations for the **Microsoft network server: Disconnect clients when logon hours expire** security policy setting. |
| [Microsoft network server: Server SPN target name validation level](microsoft-network-server-server-spn-target-name-validation-level.md)| Describes the best practices, location, and values, policy management, and security considerations for the **Microsoft network server: Server SPN target name validation level** security policy setting. |
| [Network access: Allow anonymous SID/Name translation](network-access-allow-anonymous-sidname-translation.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Allow anonymous SID/Name translation** security policy setting.|
| [Network access: Allow anonymous SID/Name translation](network-access-allow-anonymous-sidname-translation.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Allow anonymous SID/Name translation** security policy setting.|
| [Network access: Do not allow anonymous enumeration of SAM accounts](network-access-do-not-allow-anonymous-enumeration-of-sam-accounts.md)| Describes the best practices, location, values, and security considerations for the **Network access: Do not allow anonymous enumeration of SAM accounts** security policy setting. |
| [Network access: Do not allow anonymous enumeration of SAM accounts and shares](network-access-do-not-allow-anonymous-enumeration-of-sam-accounts-and-shares.md)| Describes the best practices, location, values, and security considerations for the **Network access: Do not allow anonymous enumeration of SAM accounts and shares** security policy setting. |
| [Network access: Do not allow storage of passwords and credentials for network authentication](network-access-do-not-allow-storage-of-passwords-and-credentials-for-network-authentication.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Do not allow storage of passwords and credentials for network authentication** security policy setting. |
| [Network access: Let Everyone permissions apply to anonymous users](network-access-let-everyone-permissions-apply-to-anonymous-users.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Let Everyone permissions apply to anonymous users** security policy setting. |
| [Network access: Named Pipes that can be accessed anonymously](network-access-named-pipes-that-can-be-accessed-anonymously.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Named Pipes that can be accessed anonymously** security policy setting. |
| [Network access: Remotely accessible registry paths](network-access-remotely-accessible-registry-paths.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Remotely accessible registry paths** security policy setting.|
| [Network access: Remotely accessible registry paths](network-access-remotely-accessible-registry-paths.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Remotely accessible registry paths** security policy setting.|
| [Network access: Remotely accessible registry paths and subpaths](network-access-remotely-accessible-registry-paths-and-subpaths.md)| Describes the best practices, location, values, and security considerations for the **Network access: Remotely accessible registry paths and subpaths** security policy setting. |
| [Network access: Restrict anonymous access to Named Pipes and Shares](network-access-restrict-anonymous-access-to-named-pipes-and-shares.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Restrict anonymous access to Named Pipes and Shares** security policy setting. |
| [Network access: Restrict clients allowed to make remote calls to SAM](network-access-restrict-clients-allowed-to-make-remote-sam-calls.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Restrict clients allowed to make remote calls to SAM** security policy setting. |
| [Network access: Shares that can be accessed anonymously](network-access-shares-that-can-be-accessed-anonymously.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Shares that can be accessed anonymously** security policy setting. |
| [Network access: Sharing and security model for local accounts](network-access-sharing-and-security-model-for-local-accounts.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network access: Sharing and security model for local accounts** security policy setting. |
| [Network security: Allow Local System to use computer identity for NTLM](network-security-allow-local-system-to-use-computer-identity-for-ntlm.md)| Describes the location, values, policy management, and security considerations for the **Network security: Allow Local System to use computer identity for NTLM** security policy setting. |
| [Network security: Allow LocalSystem NULL session fallback](network-security-allow-localsystem-null-session-fallback.md)| Describes the best practices, location, values, and security considerations for the **Network security: Allow LocalSystem NULL session fallback** security policy setting.|
| [Network security: Allow LocalSystem NULL session fallback](network-security-allow-localsystem-null-session-fallback.md)| Describes the best practices, location, values, and security considerations for the **Network security: Allow LocalSystem NULL session fallback** security policy setting.|
| [Network security: Allow PKU2U authentication requests to this computer to use online identities](network-security-allow-pku2u-authentication-requests-to-this-computer-to-use-online-identities.md)| Describes the best practices, location, and values for the **Network Security: Allow PKU2U authentication requests to this computer to use online identities** security policy setting. |
| [Network security: Configure encryption types allowed for Kerberos Win7 only](network-security-configure-encryption-types-allowed-for-kerberos.md)| Describes the best practices, location, values, and security considerations for the **Network security: Configure encryption types allowed for Kerberos Win7 only** security policy setting. |
| [Network security: Do not store LAN Manager hash value on next password change](network-security-do-not-store-lan-manager-hash-value-on-next-password-change.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network security: Do not store LAN Manager hash value on next password change** security policy setting. |
| [Network security: Force logoff when logon hours expire](network-security-force-logoff-when-logon-hours-expire.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network security: Force logoff when logon hours expire** security policy setting. |
| [Network security: LAN Manager authentication level](network-security-lan-manager-authentication-level.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network security: LAN Manager authentication level** security policy setting.|
| [Network security: LAN Manager authentication level](network-security-lan-manager-authentication-level.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network security: LAN Manager authentication level** security policy setting.|
| [Network security: LDAP client signing requirements](network-security-ldap-client-signing-requirements.md) | This security policy reference topic for the IT professional describes the best practices, location, values, policy management, and security considerations for this policy setting. This information applies to computers running at least the Windows Server 2008 operating system. |
| [Network security: Minimum session security for NTLM SSP based (including secure RPC) clients](network-security-minimum-session-security-for-ntlm-ssp-based-including-secure-rpc-clients.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network security: Minimum session security for NTLM SSP based (including secure RPC) clients** security policy setting. |
| [Network security: Minimum session security for NTLM SSP based (including secure RPC) servers](network-security-minimum-session-security-for-ntlm-ssp-based-including-secure-rpc-servers.md)| Describes the best practices, location, values, policy management, and security considerations for the **Network security: Minimum session security for NTLM SSP based (including secure RPC) servers** security policy setting. |
@ -116,12 +109,12 @@ For info about setting security policies, see [Configure security policy setting
| [Recovery console: Allow automatic administrative logon](recovery-console-allow-automatic-administrative-logon.md)| Describes the best practices, location, values, policy management, and security considerations for the **Recovery console: Allow automatic administrative logon** security policy setting. |
| [Recovery console: Allow floppy copy and access to all drives and folders](recovery-console-allow-floppy-copy-and-access-to-all-drives-and-folders.md)| Describes the best practices, location, values, policy management, and security considerations for the **Recovery console: Allow floppy copy and access to all drives and folders** security policy setting. |
| [Shutdown: Allow system to be shut down without having to lg on](shutdown-allow-system-to-be-shut-down-without-having-to-log-on.md)| Describes the best practices, location, values, policy management, and security considerations for the **Shutdown: Allow system to be shut down without having to log on** security policy setting. |
| [Shutdown: Clear virtual memory pagefile](shutdown-clear-virtual-memory-pagefile.md)| Describes the best practices, location, values, policy management, and security considerations for the **Shutdown: Clear virtual memory pagefile** security policy setting.|
| [Shutdown: Clear virtual memory pagefile](shutdown-clear-virtual-memory-pagefile.md)| Describes the best practices, location, values, policy management, and security considerations for the **Shutdown: Clear virtual memory pagefile** security policy setting.|
| [System cryptography: Force strong key protection for user keys stored on the computer](system-cryptography-force-strong-key-protection-for-user-keys-stored-on-the-computer.md)| Describes the best practices, location, values, policy management, and security considerations for the **System cryptography: Force strong key protection for user keys stored on the computer** security policy setting. |
| [System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing](system-cryptography-use-fips-compliant-algorithms-for-encryption-hashing-and-signing.md)| This security policy reference topic for the IT professional describes the best practices, location, values, policy management, and security considerations for this policy setting. |
| [System objects: Require case insensitivity for non-Windows subsystems](system-objects-require-case-insensitivity-for-non-windows-subsystems.md)| Describes the best practices, location, values, policy management, and security considerations for the **System objects: Require case insensitivity for non-Windows subsystems** security policy setting. |
| [System objects: Strengthen default permissions of internal system objects (e.g. Symbolic Links)](system-objects-strengthen-default-permissions-of-internal-system-objects.md)| Describes the best practices, location, values, policy management, and security considerations for the **System objects: Strengthen default permissions of internal system objects (for example, Symbolic Links)** security policy setting. |
| [System settings: Optional subsystems](system-settings-optional-subsystems.md) | Describes the best practices, location, values, policy management, and security considerations for the **System settings: Optional subsystems** security policy setting.|
| [System settings: Optional subsystems](system-settings-optional-subsystems.md) | Describes the best practices, location, values, policy management, and security considerations for the **System settings: Optional subsystems** security policy setting.|
| [System settings: Use certificate rules on Windows executables for Software Restriction Policies](system-settings-use-certificate-rules-on-windows-executables-for-software-restriction-policies.md)| Describes the best practices, location, values, policy management, and security considerations for the **System settings: Use certificate rules on Windows executables for Software Restriction Policies** security policy setting. |
| [User Account Control: Admin Approval Mode for the Built-in Administrator account](user-account-control-admin-approval-mode-for-the-built-in-administrator-account.md)| Describes the best practices, location, values, policy management, and security considerations for the **User Account Control: Admin Approval Mode for the Built-in Administrator account** security policy setting. |
| [User Account Control: Allow UIAccess applications to prompt for elevation without using the secure desktop](user-account-control-allow-uiaccess-applications-to-prompt-for-elevation-without-using-the-secure-desktop.md)| Describes the best practices, location, values, and security considerations for the **User Account Control: Allow UIAccess applications to prompt for elevation without using the secure desktop** security policy setting. |
@ -133,7 +126,7 @@ For info about setting security policies, see [Configure security policy setting
| [User Account Control: Run all administrators in Admin Approval Mode](user-account-control-run-all-administrators-in-admin-approval-mode.md)| Describes the best practices, location, values, policy management, and security considerations for the **User Account Control: Run all administrators in Admin Approval Mode** security policy setting. |
| [User Account Control: Switch to the secure desktop when prompting for elevation](user-account-control-switch-to-the-secure-desktop-when-prompting-for-elevation.md)| Describes the best practices, location, values, policy management, and security considerations for the **User Account Control: Switch to the secure desktop when prompting for elevation** security policy setting. |
| [User Account Control: Virtualize file and registry write failures to per-user locations](user-account-control-virtualize-file-and-registry-write-failures-to-per-user-locations.md)| Describes the best practices, location, values, policy management, and security considerations for the **User Account Control: Virtualize file and registry write failures to per-user locations** security policy setting. |
## Related articles
- [Security policy settings reference](security-policy-settings-reference.md)

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@ -1,120 +0,0 @@
---
title: Always sign SMBv1 network client communications (Windows 10)
description: Learn about best practices, security considerations and more for the security policy setting, Microsoft network client Digitally sign communications (always).
ms.assetid: 4b7b0298-b130-40f8-960d-60418ba85f76
ms.reviewer:
ms.author: vinpa
ms.prod: windows-client
ms.mktglfcycl: deploy
ms.sitesec: library
ms.pagetype: security
ms.localizationpriority: medium
author: vinaypamnani-msft
manager: aaroncz
audience: ITPro
ms.topic: conceptual
ms.date: 01/04/2019
ms.technology: itpro-security
---
# SMBv1 Microsoft network client: Digitally sign communications (always)
**Applies to**
- Windows 10
This topic is about the Server Message Block (SMB) v1 protocol. SMBv1 isn't secure and has been deprecated in Windows. Beginning with Windows 10 Fall Creators Update and Windows Server, version 1709, [SMBv1 isn't installed by default](/windows-server/storage/file-server/troubleshoot/smbv1-not-installed-by-default-in-windows).
The rest of this topic describes the best practices, location, values, policy management and security considerations for the **Microsoft network client: Digitally sign communications (always)** security policy setting only for SMBv1. The same policy setting can be applied to computers that run SMBv2. For more information, see [Microsoft network client: Digitally sign communications (always)](microsoft-network-client-digitally-sign-communications-always.md).
## Reference
The Server Message Block (SMB) protocol provides the basis for file and print sharing and many other networking operations, such as remote Windows administration. To prevent man-in-the-middle attacks that modify SMB packets in transit, the SMB protocol supports the digital signing of SMB packets.
This policy setting determines whether SMB packet signing must be negotiated before further communication with the Server service is permitted.
Implementation of digital signatures in high-security networks helps prevent the impersonation of client computers and servers, which is known as "session hijacking." But misuse of these policy settings is a common error that can cause data loss or problems with data access or security.
If server-side SMB signing is required, a client device won't be able to establish a session with that server, unless it has client-side SMB signing enabled. By default, client-side SMB signing is enabled on workstations, servers, and domain controllers. Similarly, if client-side SMB signing is required, that client device won't be able to establish a session with servers that don't have packet signing enabled. By default, server-side SMB signing is enabled only on domain controllers.
If server-side SMB signing is enabled, SMB packet signing will be negotiated with client computers that have SMB signing enabled.
[!INCLUDE [smb1-perf-note](includes/smb1-perf-note.md)]
There are three other policy settings that relate to packet-signing requirements for Server Message Block (SMB) communications:
- [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md)
- [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md)
- [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md)
### Possible values
- Enabled
- Disabled
- Not defined
### Best practices
1. Configure the following security policy settings as follows:
- Disable **Microsoft network client: Digitally sign communications (always)**.
- Disable [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md).
- Enable [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md).
- Enable [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md).
2. Alternately, you can set all of these policy settings to Enabled, but enabling them can cause slower performance on client devices and prevent them from communicating with legacy SMB applications and operating systems.
### Location
Computer Configuration\\Windows Settings\\Security Settings\\Local Policies\\Security Options
### Default values
The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.
| Server type or GPO | Default value |
| - | - |
| Default Domain Policy| Not defined|
| Default Domain Controller Policy | Not defined|
| Stand-Alone Server Default Settings | Disabled|
| DC Effective Default Settings | Disabled|
| Member Server Effective Default Settings | Disabled|
| Client Computer Effective Default Settings | Disabled|
## Policy management
This section describes features and tools that are available to help you manage this policy.
### Restart requirement
None. Changes to this policy become effective without a device restart when they're saved locally or distributed through Group Policy.
## Security considerations
This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.
### Vulnerability
Session hijacking uses tools that allow attackers who have access to the same network as the client device or server to interrupt, end, or steal a session in progress. Attackers can potentially intercept and modify unsigned Server Message Block (SMB) packets and then modify the traffic and forward it so that the server might perform objectionable actions. Alternatively, the attacker could pose as the server or client computer after legitimate authentication, and gain unauthorized access to data.
SMB is the resource-sharing protocol that is supported by many Windows operating systems. It's the basis of NetBIOS and many other protocols. SMB signatures authenticate users and the servers that host the data. If either side fails the authentication process, data transmission doesn't take place.
### Countermeasure
Configure the settings as follows:
- Disable **Microsoft network client: Digitally sign communications (always)**.
- Disable [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md).
- Enable [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md).
- Enable [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md).
In highly secure environments, we recommend that you configure all of these settings to Enabled. However, that configuration may cause slower performance on client devices and prevent communications with earlier SMB applications and operating systems.
>**Note:**  An alternative countermeasure that could protect all network traffic is to implement digital signatures with IPsec. There are hardware-based accelerators for IPsec encryption and signing that could be used to minimize the performance impact on the servers' CPUs. No such accelerators are available for SMB signing.
### Potential impact
Implementations of the SMB file and print-sharing protocol support mutual authentication. This mutual authentication prevents session hijacking attacks and supports message authentication to prevent man-in-the-middle attacks. SMB signing provides this authentication by placing a digital signature into each SMB, which is then verified by the client and the server.
Implementation of SMB signing may negatively affect performance because each packet must be signed and verified. If these settings are enabled on a server that is performing multiple roles, such as a small business server that is serving as a domain controller, file server, print server, and application server, performance may be substantially slowed. Additionally, if you configure devices to ignore all unsigned SMB communications, older applications and operating systems can't connect. However, if you completely disable all SMB signing, computers are vulnerable to session-hijacking attacks.
## Related topics
- [Security Options](security-options.md)

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@ -1,122 +0,0 @@
---
title: SMBv1 Microsoft network client Digitally sign communications (if server agrees) (Windows 10)
description: Best practices, location, values, and security considerations for the policy setting, Microsoft network client Digitally sign communications (if server agrees).
ms.assetid: e553f700-aae5-425c-8650-f251c90ba5dd
ms.reviewer:
ms.author: vinpa
ms.prod: windows-client
ms.mktglfcycl: deploy
ms.sitesec: library
ms.pagetype: security
ms.localizationpriority: medium
author: vinaypamnani-msft
manager: aaroncz
audience: ITPro
ms.topic: conceptual
ms.date: 01/04/2019
ms.technology: itpro-security
---
# SMBv1 Microsoft network client: Digitally sign communications (if server agrees)
**Applies to**
- Windows 10
This topic is about the Server Message Block (SMB) v1 protocol. SMBv1 isn't secure and has been deprecated in Windows. Beginning with Windows 10 Fall Creators Update and Windows Server, version 1709, [SMBv1 isn't installed by default](/windows-server/storage/file-server/troubleshoot/smbv1-not-installed-by-default-in-windows).
The rest of this topic describes the best practices, location, values, and security considerations for the **Microsoft network client: Digitally sign communications (if server agrees)** security policy setting only for SMBv1. The same policy setting can be applied to computers that run SMBv2. For more information, see [Microsoft network client: Digitally sign communications (if server agrees)](microsoft-network-client-digitally-sign-communications-always.md).
## Reference
The Server Message Block (SMB) protocol provides the basis for Microsoft file and print sharing and many other networking operations, such as remote Windows administration. To prevent man-in-the-middle attacks that modify SMB packets in transit, the SMB protocol supports the digital signing of SMB packets. This policy setting determines whether SMB packet signing must be negotiated before further communication with the Server service is permitted.
Implementation of digital signatures in high-security networks helps to prevent the impersonation of client computers and servers, which is known as "session hijacking." But misuse of these policy settings is a common error that can cause data loss or problems with data access or security.
If server-side SMB signing is required, a client computer won't be able to establish a session with that server, unless it has client-side SMB signing enabled. By default, client-side SMB signing is enabled on workstations, servers, and domain controllers. Similarly, if client-side SMB signing is required, that client device won't be able to establish a session with servers that don't have packet signing enabled. By default, server-side SMB signing is enabled only on domain controllers.
If server-side SMB signing is enabled, SMB packet signing will be negotiated with client computers that have SMB signing enabled.
[!INCLUDE [smb1-perf-note](includes/smb1-perf-note.md)]
There are three other policy settings that relate to packet-signing requirements for Server Message Block (SMB) communications:
- [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md)
- [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md)
- [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md)
### Possible values
- Enabled
- Disabled
- Not defined
### Best practices
- Configure the following security policy settings as follows:
- Disable [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md).
- Disable [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md).
- Enable **Microsoft Network Client: Digitally Sign Communications (If Server Agrees)**.
- Enable [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md).
- Alternately, you can set all of these policy settings to Enabled, but enabling them can cause slower performance on client devices and prevent them from communicating with legacy SMB applications and operating systems.
### Location
Computer Configuration\\Windows Settings\\Security Settings\\Local Policies\\Security Options
### Default values
The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.
| Server type or GPO | Default value |
| - | - |
| Default Domain Policy| Not defined|
| Default Domain Controller Policy | Not defined|
| Stand-Alone Server Default Settings | Enabled|
| DC Effective Default Settings | Enabled|
| Member Server Effective Default Settings| Enabled|
| Client Computer Effective Default Settings | Enabled|
## Policy management
This section describes features and tools that are available to help you manage this policy.
### Restart requirement
None. Changes to this policy become effective without a device restart when they're saved locally or distributed through Group Policy.
## Security considerations
This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.
### Vulnerability
Session hijacking uses tools that allow attackers who have access to the same network as the client or server to interrupt, end, or steal a session in progress. Attackers can potentially intercept and modify unsigned Server Message Block (SMB) packets and then modify the traffic and forward it so
that the server might perform objectionable actions. Alternatively, the attacker could pose as the server or client device after legitimate authentication and gain unauthorized access to data.
SMB is the resource-sharing protocol that is supported by many Windows operating systems. It's the basis of NetBIOS and many other protocols. SMB signatures authenticate users and the servers that host the data. If either side fails the authentication process, data transmission doesn't take place.
### Countermeasure
Configure the settings as follows:
- Disable [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md).
- Disable [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md).
- Enable **Microsoft network client: Digitally sign communications (if server agrees)**.
- Enable [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md).
In highly secure environments, we recommend that you configure all of these settings to Enabled. However, that configuration may cause slower performance on client devices and prevent communications with earlier SMB applications and operating systems.
> [!NOTE]
> An alternative countermeasure that could protect all network traffic is to implement digital signatures with IPsec. There are hardware-based accelerators for IPsec encryption and signing that could be used to minimize the performance impact on the servers' CPUs. No such accelerators are available for SMB signing.
### Potential impact
Implementations of the SMB file and print-sharing protocol support mutual authentication. This mutual authentication prevents session hijacking attacks and supports message authentication to prevent man-in-the-middle attacks. SMB signing provides this authentication by placing a digital signature into each SMB, which is then verified by the client and the server.
Implementation of SMB signing may negatively affect performance because each packet must be signed and verified. If these settings are enabled on a server that is performing multiple roles, such as a small business server that is serving as a domain controller, file server, print server, and application server, performance may be substantially slowed. Additionally, if you configure devices to ignore all unsigned SMB communications, older applications and operating systems can't connect. However, if you completely disable all SMB signing, devices are vulnerable to session-hijacking
attacks.
## Related topics
- [Security Options](security-options.md)

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@ -1,123 +0,0 @@
---
title: SMB v1 Microsoft network server Digitally sign communications (always) (Windows 10)
description: Best practices, security considerations, and more for the security policy setting, Microsoft network server Digitally sign communications (always).
ms.assetid: 2007b622-7bc2-44e8-9cf1-d34b62117ea8
ms.reviewer:
ms.author: vinpa
ms.prod: windows-client
ms.mktglfcycl: deploy
ms.sitesec: library
ms.pagetype: security
ms.localizationpriority: medium
author: vinaypamnani-msft
manager: aaroncz
audience: ITPro
ms.topic: conceptual
ms.date: 01/04/2019
ms.technology: itpro-security
---
# SMB v1 Microsoft network server: Digitally sign communications (always)
**Applies to**
- Windows 10
This topic is about the Server Message Block (SMB) v1 protocol. SMBv1 isn't secure and has been deprecated in Windows. Beginning with Windows 10 Fall Creators Update and Windows Server, version 1709, [SMB v1 isn't installed by default](/windows-server/storage/file-server/troubleshoot/smbv1-not-installed-by-default-in-windows).
The rest of this topic describes the best practices, location, values, policy management and security considerations for the **Microsoft network server: Digitally sign communications (always)** security policy setting only for SMBv1. The same policy setting can be applied to computers that run SMBv2. Fore more information, see [Microsoft network server: Digitally sign communications (always)](microsoft-network-server-digitally-sign-communications-always.md).
## Reference
The Server Message Block (SMB) protocol provides the basis for file and print sharing and many other networking operations, such as remote Windows administration. To prevent man-in-the-middle attacks that modify SMB packets in transit, the SMB protocol supports the digital signing of SMB packets.
This policy setting determines whether SMB packet signing must be negotiated before further communication with the Server service is permitted.
Implementation of digital signatures in high-security networks helps to prevent the impersonation of client computers and servers, which is known as "session hijacking." But misuse of these policy settings is a common error that can cause data loss or problems with data access or security.
For this policy to take effect on computers running Windows 2000, client-side packet signing must also be enabled. To enable client-side SMB packet signing, set [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md). Devices that have this policy set won't be able to communicate with devices that don't have server-side packet signing enabled. By default, server-side packet signing is enabled only on domain controllers. Server-side packet signing can be enabled on devices by setting [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md).
If server-side SMB signing is required, a client device won't be able to establish a session with that server, unless it has client-side SMB signing enabled. By default, client-side SMB signing is enabled on workstations, servers, and domain controllers. Similarly, if client-side SMB signing is required, that client device won't be able to establish a session with servers that don't have packet signing enabled. By default, server-side SMB signing is enabled only on domain controllers.
If server-side SMB signing is enabled, SMB packet signing will be negotiated with client devices that have SMB signing enabled.
[!INCLUDE [smb1-perf-note](includes/smb1-perf-note.md)]
There are three other policy settings that relate to packet-signing requirements for Server Message Block (SMB) communications:
- [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md)
- [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md)
- [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md)
### Possible values
- Enabled
- Disabled
- Not defined
### Best practices
1. Configure the following security policy settings as follows:
- Disable [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md).
- Disable **Microsoft network server: Digitally sign communications (always)**.
- Enable [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md).
- Enable [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md).
2. Alternately, you can set all of these policy settings to Enabled, but enabling them can cause slower performance on client devices and prevent them from communicating with legacy SMB applications and operating systems.
### Location
Computer Configuration\\Windows Settings\\Security Settings\\Local Policies\\Security Options
### Default values
The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.
| Server type or GPO | Default value |
| - | - |
| Default Domain Policy| Not defined|
| Default Domain Controller Policy | Enabled|
| Stand-Alone Server Default Settings | Not defined|
| DC Effective Default Settings | Enabled|
| Member Server Effective Default Settings| Not defined|
| Client Computer Effective Default Settings | Disabled|
## Policy management
This section describes features and tools that are available to help you manage this policy.
### Restart requirement
None. Changes to this policy become effective without a device restart when they're saved locally or distributed through Group Policy.
## Security considerations
This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.
### Vulnerability
Session hijacking uses tools that allow attackers who have access to the same network as the client device or server to interrupt, end, or steal a session in progress. Attackers can potentially intercept and modify unsigned Server Message Block (SMB) packets and then modify the traffic and forward it so that the server might perform objectionable actions. Alternatively, the attacker could pose as the server or client device after legitimate authentication and gain unauthorized access to data.
SMB is the resource-sharing protocol that is supported by many Windows operating systems. It's the basis of NetBIOS and many other protocols. SMB signatures authenticate users and the servers that host the data. If either side fails the authentication process, data transmission doesn't take place.
### Countermeasure
Configure the settings as follows:
- Disable [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md).
- Disable **Microsoft network server: Digitally sign communications (always)**.
- Enable [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md).
- Enable [Microsoft network server: Digitally sign communications (if client agrees)](smbv1-microsoft-network-server-digitally-sign-communications-if-client-agrees.md).
In highly secure environments, we recommend that you configure all of these settings to Enabled. However, that configuration may cause slower performance on client devices and prevent communications with earlier SMB applications and operating systems.
>**Note:**  An alternative countermeasure that could protect all network traffic is to implement digital signatures with IPsec. There are hardware-based accelerators for IPsec encryption and signing that could be used to minimize the performance impact on the servers' CPUs. No such accelerators are available for SMB signing.
### Potential impact
Implementations of the SMB file and print-sharing protocol support mutual authentication. This mutual authentication prevents session hijacking attacks and supports message authentication to prevent man-in-the-middle attacks. SMB signing provides this authentication by placing a digital signature into each SMB, which is then verified by the client and the server.
Implementation of SMB signing may negatively affect performance because each packet must be signed and verified. If these settings are enabled on a server that is performing multiple roles, such as a small business server that is serving as a domain controller, file server, print server, and application server, performance may be substantially slowed. Additionally, if you configure computers to ignore all unsigned SMB communications, older applications and operating systems can't connect. However, if you completely disable all SMB signing, devices are vulnerable to session-hijacking attacks.
## Related topics
- [Security Options](security-options.md)

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@ -1,122 +0,0 @@
---
title: SMBv1 Microsoft network server Digitally sign communications (if client agrees) (Windows 10)
description: Best practices, security considerations and more for the security policy setting, Microsoft network server Digitally sign communications (if client agrees).
ms.assetid: c92b2e3d-1dbf-4337-a145-b17a585f4fc1
ms.reviewer:
ms.author: vinpa
ms.prod: windows-client
ms.mktglfcycl: deploy
ms.sitesec: library
ms.pagetype: security
ms.localizationpriority: medium
author: vinaypamnani-msft
manager: aaroncz
audience: ITPro
ms.topic: conceptual
ms.date: 01/04/2019
ms.technology: itpro-security
---
# SMBv1 Microsoft network server: Digitally sign communications (if client agrees)
**Applies to**
- Windows 10
This topic is about the Server Message Block (SMB) v1 protocol. SMBv1 isn't secure and has been deprecated in Windows. Beginning with Windows 10 Fall Creators Update and Windows Server, version 1709, [SMBv1 isn't installed by default](/windows-server/storage/file-server/troubleshoot/smbv1-not-installed-by-default-in-windows).
The rest of this topic describes the best practices, location, values, policy management and security considerations for the **Microsoft network server: Digitally sign communications (if client agrees)** security policy setting only for SMBv1. The same policy setting can be applied to computers that run SMBv2. For more information, see [Microsoft network server: Digitally sign communications (if client agrees)](microsoft-network-server-digitally-sign-communications-always.md).
## Reference
The Server Message Block (SMB) protocol provides the basis for file and print sharing and many other networking operations, such as remote Windows administration. To prevent man-in-the-middle attacks that modify SMB packets in transit, the SMB protocol supports the digital signing of SMB packets.
This policy setting determines whether SMB packet signing must be negotiated before further communication with the Server service is permitted.
Implementation of digital signatures in high-security networks helps to prevent the impersonation of client computers and servers, which is known as "session hijacking." But misuse of these policy settings is a common error that can cause data loss or problems with data access or security.
If server-side SMB signing is required, a client device won't be able to establish a session with that server, unless it has client-side SMB signing enabled. By default, client-side SMB signing is enabled on workstations, servers, and domain controllers. Similarly, if client-side SMB signing is required, that client device won't be able to establish a session with servers that don't have packet signing enabled. By default, server-side SMB signing is enabled only on domain controllers.
If server-side SMB signing is enabled, SMB packet signing will be negotiated with client computers that have SMB signing enabled.
[!INCLUDE [smb1-perf-note](includes/smb1-perf-note.md)]
There are three other policy settings that relate to packet-signing requirements for Server Message Block (SMB) communications:
- [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md)
- [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md)
- [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md)
### Possible values
- Enabled
- Disabled
- Not defined
### Best practices
1. Configure the following security policy settings as follows:
- Disable [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md).
- Disable [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md).
- Enable [Microsoft Network Client: Digitally Sign Communications (If Server Agrees)](smbv1-microsoft-network-server-digitally-sign-communications-always.md).
- Enable **Microsoft Network Server: Digitally Sign Communications (If Client Agrees)**.
2. Alternately, you can set all of these policy settings to Enabled, but enabling them can cause slower performance on client devices and prevent them from communicating with legacy SMB applications and operating systems.
### Location
Computer Configuration\\Windows Settings\\Security Settings\\Local Policies\\Security Options
### Default values
The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.
| Server type or GPO Default value |
|--------------------------------------------|
| Default Domain Policy |
| Default Domain Controller Policy |
| Stand-Alone Server Default Settings |
| DC Effective Default Settings |
| Member Server Effective Default Settings |
| Client Computer Effective Default Settings |
## Policy management
This section describes features and tools that are available to help you manage this policy.
### Restart requirement
None. Changes to this policy become effective without a computer restart when they're saved locally or distributed through Group Policy.
## Security considerations
This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation.
### Vulnerability
Session hijacking uses tools that allow attackers who have access to the same network as the client device or server to interrupt, end, or steal a session in progress. Attackers can potentially intercept and modify unsigned Server Message Block (SMB) packets and then modify the traffic and forward it so that the server might perform objectionable actions. Alternatively, the attacker could pose as the server or client computer after legitimate authentication and gain unauthorized access to data.
SMB is the resource-sharing protocol that is supported by many Windows operating systems. It's the basis of NetBIOS and many other protocols. SMB signatures authenticate users and the servers that host the data. If either side fails the authentication process, data transmission doesn't take place.
### Countermeasure
Configure the settings as follows:
- Disable [Microsoft network client: Digitally sign communications (always)](smbv1-microsoft-network-client-digitally-sign-communications-always.md).
- Disable [Microsoft network server: Digitally sign communications (always)](smbv1-microsoft-network-server-digitally-sign-communications-always.md).
- Enable [Microsoft network client: Digitally sign communications (if server agrees)](smbv1-microsoft-network-client-digitally-sign-communications-if-server-agrees.md).
- Enable **Microsoft network server: Digitally sign communications (if client agrees)**.
In highly secure environments, we recommend that you configure all of these settings to Enabled. However, that configuration may cause slower performance on client devices and prevent communications with earlier SMB applications and operating systems.
>**Note:** An alternative countermeasure that could protect all network traffic is to implement digital signatures with IPsec. There are hardware-based accelerators for IPsec encryption and signing that could be used to minimize the performance impact on the servers' CPUs. No such accelerators are available for SMB signing.
### Potential impact
SMB file and print-sharing protocol support mutual authentication. This mutual authentication prevents session hijacking attacks and supports message authentication to prevent man-in-the-middle attacks. SMB signing provides this authentication by placing a digital signature into each SMB, which is then verified by the client and the server.
Implementation of SMB signing may negatively affect performance because each packet must be signed and verified. If these settings are enabled on a server that is performing multiple roles, such as a small business server that is serving as a domain controller, file server, print server, and application server, performance may be substantially slowed. Additionally, if you configure computers to ignore all unsigned SMB communications, older applications and operating systems can't connect. However, if you completely disable all SMB signing, computers are vulnerable to session-hijacking attacks.
## Related topics
- [Security Options](security-options.md)