Malicious PDF — malware analysis report

Static analysis result for SHA-256 a33b02e62e64df10…

MALICIOUS

PDF

3.8 KB
MD5: cb9fa3522c6a28fadc2d0ccc7a3575d1 SHA-1: 6fee317ed7704a976f1062acf59520d473688cbb SHA-256: a33b02e62e64df102b091cec639d1b0200ea00b5abaeca90409fede1e14f8c4e
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/Shell Script Execution: JavaScript T1204.002 Malicious File: Malicious JavaScript

The PDF sample was flagged by a critical ClamAV detection (Pdf.Exploit.Agent-36178) and a high-confidence ML classifier, indicating it contains an exploit. Heuristics confirm the presence of embedded JavaScript, string decoding functions (fromCharCode, ASCIIHexDecode, ASCII85Decode), and JavaScript actions, all common indicators of PDF exploits. The ML classifier's high score suggests the exploit is likely functional and intended to deliver a malicious payload.

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