Malicious PDF — malware analysis report

Static analysis result for SHA-256 71c5a11958fb4b32…

MALICIOUS

PDF

33.7 KB
MD5: ef2bf9d875ea5bd05052fb41d851f801 SHA-1: 82d149865ba3c768c3a824a0bfb93e8d77d29a3d SHA-256: 71c5a11958fb4b32b260899a190efc51e65e5e59a231a4a01bc0530c89d88753
74 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript and uses decoding filters (ASCIIHexDecode, ASCII85Decode) that are often employed to obfuscate malicious code. The ML classifier strongly indicates maliciousness, suggesting the JavaScript is likely designed to exploit a vulnerability for client execution, commonly delivered via spearphishing attachments.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • ASCII85Decode filter (with exploit indicators) low PDF_FILTER_85
    ASCII85 encoding filter present alongside exploit delivery indicators — uncommon outside of obfuscation