Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c2b1f5945f69fbe…

MALICIOUS

PDF

3.9 KB
MD5: 01409cc20a3b4627bda4b3b77090b1a0 SHA-1: 5e2f7ab89137ed8706b633755c571c5f5a7fb9b6 SHA-256: 4c2b1f5945f69fbe4c8343dc9e12603cef754a70058cfb88c89eb6b21983452b
142 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1566.002 Phishing: Spearphishing Attachment T1059.001 Command and Scripting Interpreter: PowerShell

The file is a PDF that triggered multiple high-severity heuristics, including ClamAV detection for 'Pdf.Exploit.Agent-36178' and a high ML classifier score. The presence of JavaScript actions, embedded JS streams, and the use of ASCIIHexDecode and ASCII85Decode filters strongly indicate an exploit attempt within the PDF. While no specific document body text was readable, the combination of these indicators points to a malicious PDF designed to exploit a vulnerability and likely download a second-stage 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