Malicious PDF — malware analysis report

Static analysis result for SHA-256 943990fca23a40ad…

MALICIOUS

PDF

3.9 KB
MD5: 0877014d0eb643b9db929aa219b893c1 SHA-1: 460623e2f1ab941e874111e755992229d0cf8303 SHA-256: 943990fca23a40adb710879d0bcfb9588bc5d35710b01bddf710e75aba2fab48
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/Shell Scripting: JavaScript T1204.002 Malicious File: Malicious PDF

The file is a PDF containing embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT and PDF_JS. The ML classifier and ClamAV detection strongly suggest malicious intent, specifically targeting PDF exploits. The presence of ASCIIHexDecode and ASCII85Decode filters further supports the exploitation of PDF vulnerabilities. No specific family could be identified, but the techniques point to a malicious PDF dropper.

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