E-mail messages with Powerpoint attachments are not blocked by the Block Image Files rule


This article applies to:

  • Trustwave MailMarshal (SEG)
  • Trustwave ECM/MailMarshal Exchange

Symptoms:

  • E-mail messages with Powerpoint attachments are not blocked by the Block Image Files rule.
  • MailMarshal is not blocking e-mail, containing Microsoft Powerpoint (.pps) attachments, with the rule 'Block IMAGE Files' type 'Powerpoint Show' enabled.

Causes:

It is possible for the 'Powerpoint Show' document header data to become corrupted and to be incorrecty classified by MailMarshal as type OLE.

Reply:

The recommended resolution is to upgrade to the latest version of MailMarshal. Current versions have significant improvements in document type detection.

It is also possible to block by file name (such as .pps) as well as by type.

If you want to block on either criterion, create separate rules. Adding two criteria to the same rule will require both to be true for the rule to trigger.

This article was previously published as:
NETIQKB29663
Marshal KB367

Last Modified 5/1/2020.
https://support.trustwave.com/kb/KnowledgebaseArticle10072.aspx