Cisco Cisco Email Security Appliance C170 Guia Do Utilizador

Messages are considered encrypted if the engine is unable to finish the scan due 
to an encrypted or protected field in the message. Messages that are marked 
encrypted may also be repaired.

Note the differences between the encryption detection message filter rule (refer to 
“Encryption Detection Rule” in the “Using Message Filters to Enforce Email 
Policies” chapter of the Cisco IronPort AsyncOS for Email Advanced 
Configuration Guide) and the virus scanning actions for “encrypted” messages. 
The encrypted message filter rule evaluates to “true” for any messages that are 
PGP or S/MIME encrypted. The encrypted rule can only detect PGP and S/MIME 
encrypted data. It does not detect password protected ZIP files, or Microsoft Word 
and Excel documents that include encrypted content. The virus scanning engine 
considers any message or attachment that is password protected to be “encrypted.” 

If you upgrade from a 3.8 or earlier version of AsyncOS and you configured 
Sophos Anti-Virus scanning, you must configure the Encrypted Message 
Handling section after you upgrade.

Messages are considered unscannable if a scanning timeout value has been 
reached, or the engine becomes unavailable due to an internal error. Messages that 
are marked unscannable may also be repaired.

The system may be unable to drop the attachment or completely repair a message. 
In these cases, you can configure how the system handles messages that could still 
contain viruses. 

The configuration options are the same for encrypted messages, unscannable 
messages, and virus messages.