Top Malicious Attachment Types

Can you or your staff identify potentially malicious email attachments? 

Many of us would be quick to answer ‘yes’ until we consider that nearly 50% of malicious email attachments are Microsoft Office files such as Word, Excel or PowerPoint. 

Many of these attachments are macro-enabled but not all, so all management and staff need to receive training in identifying potentially malicious attachments without opening them. Files with macros-enabled allow criminals to embed malicious code that runs in the background when the file is opened. 

It is often difficult to know which malicious attachments contain malware or viruses. The most reliable procedure is to assume all email attachments are unsafe, but the tips below can help you determine if an email and its attachments could be dangerous:

• Only open emails and attachments from a known sender
• Only open attachments that you expect to receive, E.g., if your accountant usually sends you Excel documents, be alert if you suddenly receive a Word document from then. Word documents
• Assume any hyperlinks in documents are suspect unless there is an apparent reason for them being there. And, even then, remain cautious before using them.
• If an email still doesn't feel right, err on the side of caution and contact the sender via phone or direct message to validate the authenticity.

Management and IT staff can take the following steps to further staff:

• Encourage staff to use approved document sharing platforms such as OneDrive, Google Drive, and Dropbox as an alternative to email to distribute documents internally and externally. 
• Block macro-enabled Office documents via your anti-spam system. 
• Enable attachment scanning and safe links via your anti-spam system.