What are Microsoft Office Macros and how do they work?
Macro malware hides in Microsoft Office files. Any Microsoft document can contain embedded code (Macros) written in Microsoft’s Visual Basic for Applications (VBA) programming language. These Macros can contain a series of commands that can be recorded and replayed at a later time. Macros are a legitimate functionality in Microsoft documents and are very useful. However, Macros can also be used to perform malicious activities.
Bad actors use Microsoft files with embedded Macros as part of phishing emails targeting users within an organisation. When a user opens the file, the Macro executes, performing malicious activity. This technique is one of the most prolific ways of compromising an organisation’s network and has a very high success rate.
It is difficult for anti-virus software to determine which Macros are malicious; as the software may be behaving as designed.