Malicious PDF — malware analysis report

Static analysis result for SHA-256 a28f9703fbb559dc…

MALICIOUS

PDF

3.8 KB
MD5: 366e9aae309f13881de5e98e908c8fab SHA-1: 8ac8cef60b002ff3776e2ce7b55018da70322445 SHA-256: a28f9703fbb559dc98d109fc837267ee79fb6cfcb61604d2d95d87ccdd11d4a7
142 Risk Score

Malware Insights

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

The ML classifier and ClamAV detection strongly indicate this PDF is malicious, specifically targeting a PDF exploit. The presence of PDF JavaScript actions and embedded JS streams, along with the use of ASCIIHexDecode and ASCII85Decode filters, suggests the file attempts to leverage a known PDF vulnerability to execute arbitrary code. The high confidence score from the ML model and the critical ClamAV detection further support 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