Title

Software must be disallowed to run or install with invalid signatures. (Cat II impact)

Discussion

Microsoft ActiveX controls and file downloads often have digital signatures attached that certify the file's integrity and the identity of the signer (creator) of the software. Such signatures help ensure unmodified software is downloaded and the user can positively identify the signer to determine whether you trust them enough to run their software. The validity of unsigned code cannot be ascertained.

Check Content

Note: Some legitimate software and controls may have an invalid signature. You should carefully test such software in isolation before it is allowed to be used on an organization's network. The policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Advanced Page -> "Allow software to run or install even if the signature is invalid" must be “Disabled”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Internet Explorer\Download Criteria: If the value RunInvalidSignatures is REG_DWORD = 0, this is not a finding.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Internet Explorer -> Internet Control Panel -> Advanced Page -> "Allow software to run or install even if the signature is invalid" to “Disabled”.

Additional Identifiers

Rule ID: SV-40627r2_rule

Vulnerability ID: V-15499

Group Title: DTBI350 - Software with invalid signatures

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.