Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bc7d5b56684b6cc…

MALICIOUS

PDF

118.5 KB
MD5: e3c7d8b81485f7965b75ddc8e3ec5980 SHA-1: 5f7b01479aec38f4fe7c66466b681c5f4844cfb6 SHA-256: 4bc7d5b56684b6ccef3afeac5632d75349d4309c8120eace2b005a9d9e9aed97
196 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, including a large comment-padded eval stager, which is a common technique for obfuscating malicious code. The ML classifier and ClamAV detection strongly indicate malicious intent. The primary attack vector appears to be the exploitation of PDF vulnerabilities via JavaScript execution, as evidenced by the 'PDF_EVAL' and 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' heuristics. The specific ClamAV detection 'Pdf.Exploit.Agent-36086' further supports this.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Large comment-padded JavaScript eval stager high PDF_JS_LARGE_COMMENT_PADDED_EVAL
    PDF JavaScript contains a very large stream padded with long random-looking block comments around String.fromCharCode and eval. This is an exploit-kit obfuscation shape used to bury a decoder and recovered stage inside noise, not normal PDF form automation.
  • 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)
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
f7a8183abb6ae2ea5b495972a35ca624fc1d36a0252de2b5bc3d34fb326baf1a
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626657 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 42 long base64-like blob(s).