The Windows SMB client must be configured to always perform SMB packet signing.

From Windows 8/8.1 Security Technical Implementation Guide

Part of SMB Client Packet Signing (Always)

SV-48132r1_rule The Windows SMB client must be configured to always perform SMB packet signing.

Vulnerability discussion

The server message block (SMB) protocol provides the basis for many network operations. Digitally signed SMB packets aid in preventing man-in-the-middle attacks. If this policy is enabled, the SMB client will only communicate with an SMB server that performs SMB packet signing.

Check content

Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.) Expand the Security Configuration and Analysis tree view. Navigate to Local Policies -> Security Options. If the value for "Microsoft Network Client: Digitally sign communications (always)" is not set to "Enabled", this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \System\CurrentControlSet\Services\LanmanWorkstation\Parameters\ Value Name: RequireSecuritySignature Value Type: REG_DWORD Value: 1

Fix text

Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "Microsoft Network Client: Digitally sign communications (always)" to "Enabled".

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.