Malicious PDF — malware analysis report

Static analysis result for SHA-256 ecfed672f66f3df6…

MALICIOUS

PDF

3.8 KB
MD5: ca31519285f03e4441ac9d905ea0f4e7 SHA-1: 8de28e77e3d3369bce1dea29e5359babcd350efb SHA-256: ecfed672f66f3df62110f6083b535dc81a3fe1cc1b3bf3ca8cea587694386496
142 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by a machine learning classifier and ClamAV, which identified it as Pdf.Exploit.Agent-36178. Static analysis revealed embedded JavaScript, including the use of String.fromCharCode and ASCIIHexDecode/ASCII85Decode filters, indicating an attempt to obfuscate malicious code. The primary attack pattern involves exploiting a PDF vulnerability to execute this embedded JavaScript, likely to download and run a secondary 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