Malicious PDF — malware analysis report

Static analysis result for SHA-256 d1394d98f93a690f…

MALICIOUS

PDF

3.9 KB
MD5: 1559c4651dd65f4e7f8d7de81b199c8f SHA-1: 8817cd4ca0f2c91c28286e8688c9a5751190b9f9 SHA-256: d1394d98f93a690f6f9b1b35a80db74ee3322e7a8af0a7c99be0dbba54c8cc18
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1204.002 Malicious JavaScript

The PDF sample triggered multiple heuristics related to JavaScript execution and decoding filters, including a high-confidence ML classifier and critical ClamAV detection. The presence of embedded JavaScript and the use of filters like ASCIIHexDecode and ASCII85Decode strongly indicate an attempt to exploit a PDF vulnerability and execute malicious code. The ML classifier's output of 0.999983 further supports this assessment.

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