Malware Distribution

66.6% of total malware is delivered through PDF files attached to malicious emails, according to Palo Alto Networks Unit 42 Research

Palo Alto Networks, the global cybersecurity leader, recently released the Unit 42 Network Threat Trends Research Report Vol.2. The report highlights the current trends in malware while providing a detailed analysis of the most common types of malware and their distribution methods.

According to the research, 66.6% of total malware is delivered through portable document format (PDF) files attached to malicious emails. PDF files are commonly used in a business-environment, and victims are less likely to be wary of an expected file type, versus unexpected file types like EXEs. They could also simply be unaware that this type of file could be used for nefarious purposes.

Most people are aware of warnings against clicking strange links in emails, so PDF phishing schemes could fly under their radar better than a text-based email with just a plain link. Naming conventions expected in a business context like invoice_AUG_4601582.pdf or Updated Salary Evaluation could lure unsuspecting targets into opening these attachments. The attachments themselves might contain a URL link to click, or a button that sends victims to a website with a malicious purpose.