Things to watch out for are:
- Blank documents;
- Documents that contain random characters or symbols; and
- Documents from an untrusted source that prompt you to enable content/macros.
The following is a malicious Excel document with the suspicious objects marked in red (CLICK to enlarge image):
- Don’t open documents from unknown users.
- Watch out for suspicious file names.
- Do not click on “Enable Content” unless you are certain the document is from a trusted sender and are confident of the document’s contents.