Malicious PDF — malware analysis report

Static analysis result for SHA-256 cc4ba52b87d8053e…

MALICIOUS

PDF

5.2 KB
MD5: 070d23a2366efd3318f74f4ee62efc77 SHA-1: 1f232f0bd586b0dd69686a03d9202882e8085a36 SHA-256: cc4ba52b87d8053efac293269b4ebbe353170395923e3bae6622827e0e9a0afa
144 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1566.002 Spearphishing Attachment

This PDF file was flagged as malicious by ML classifiers and ClamAV, specifically identified as Pdf.Exploit.Agent-36178. Static analysis revealed embedded JavaScript, including the use of String.fromCharCode and various decoding filters (ASCIIHexDecode, ASCII85Decode), indicating an attempt to obfuscate malicious code. The primary attack vector appears to be exploiting a PDF vulnerability to execute this script, likely to download and execute a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • 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
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.

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