Warning about invalid signatures must be enforced.

From Microsoft Outlook 2010

SV-33571r1_rule Warning about invalid signatures must be enforced.

Vulnerability discussion

If users open e-mail messages that include invalid digital signatures, Outlook displays a warning dialog box. Users can decide whether they want to be warned about invalid signatures in the future. If users are not notified about invalid signatures, they might be prevented from detecting a fraudulent signature sent by a malicious person.

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Fix text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Cryptography “Signature Warning” to “Enabled (Always warn about invalid signatures)”.

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