Definition
Macro Virus
A macro virus is malware that exploits the macro scripting capabilities of applications (particularly Microsoft Office programs) to replicate and spread. It typically infects document templates, causing all newly created documents to carry the malicious code.
Behaviour
Macro viruses are embedded in document files and execute when the document is opened. They can:
- propagate by emailing copies of themselves to contacts
- modify template files (e.g.
Normal.dot) to infect future documents - carry payloads that corrupt or exfiltrate data
Examples
Melissa (1999)
The Melissa macro virus spread via Microsoft Outlook, sending itself to the first 50 contacts in a victim’s address book. It infected the global document template and caused widespread email traffic disruption.