Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5b3ef5460bd5ebb…

MALICIOUS

PDF

3.8 KB
MD5: a798939fc92578ab8785e9cc353fc32f SHA-1: 8f440fbd8cb3fdce48db91a32fda8ea8d86c3578 SHA-256: b5b3ef5460bd5ebbfed2458d4cfca21229f41c8d1c67a30d799401613c51017b
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT and PDF_JS. The ML classifier and ClamAV detection strongly suggest this is a malicious PDF exploiting a vulnerability. The presence of ASCIIHexDecode and ASCII85Decode filters, often used for obfuscation in exploits, further supports this. The JavaScript's exact function is not detailed, but its presence in a flagged exploit PDF is highly suspicious.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • ClamAV: Pdf.Exploit.Agent-36178 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36178
  • 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • ASCII85Decode filter (with exploit indicators) low PDF_FILTER_85
    ASCII85 encoding filter present alongside exploit delivery indicators — uncommon outside of obfuscation