Cisco Cisco Email Security Appliance C160 Mode D'Emploi

The 

signed

 rule checks messages for a signature. The rule returns a boolean value 

to indicate if the message is signed or not. This rule evaluates whether the 
signature is encoded according to ASN.1 DER encoding rules and that it conforms 
to the CMS SignedData Type structure (RFC 3852, Section 5.1.). It does not aim 
to validate whether the signature matches the content, nor does it check the 
validity of the certificate.

The following example shows a 

signed

 rule used to insert headers into a signed 

message:

signedcheck: if signed { insert-header("X-Signed", "True"); }

The following example shows a 

signed

 rule used to drop attachments from 

unsigned messages from a certain sender group:

            quarantine("forged");

        }

    } else {

        # User claims to be an completely different user

        quarantine("forged");

    }

}

Signed: if ((sendergroup == "NOTTRUSTED") AND NOT signed) {

 html-convert();

    if (attachment_size > 0)

    {

        drop_attachments("");