Malicious PDF — malware analysis report

Static analysis result for SHA-256 21bdb79d88844b10…

MALICIOUS

PDF

3.9 KB
MD5: e47dcc8518d09c3106c991862b870763 SHA-1: 9e6ead0a80c7df036cb63cfec251448854c3f777 SHA-256: 21bdb79d88844b10c2141cf2d4476b11fd3310fc4badd4cda92ebf6dab3a77c1
142 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by PDF_JAVASCRIPT and PDF_JS heuristics. The presence of PDF_FILTER_HEX and PDF_FILTER_85 filters, along with a high ML classifier score and ClamAV detection (Pdf.Exploit.Agent-36178), strongly suggests exploitation of a PDF vulnerability. The embedded JavaScript is likely used to download and execute a second-stage payload, although the specific actions are not discernible from the provided evidence.

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