Malicious PDF — malware analysis report

Static analysis result for SHA-256 25ecbd40bb614652…

MALICIOUS

PDF

118.6 KB
MD5: ae288ac27b43d664cb6f5cb682b37411 SHA-1: b1e7356847ccf0244c73cbd5d801ff9197e4c0b0 SHA-256: 25ecbd40bb6146524ba6ae0ac12d6f774806229f5a09d8c35c8e13a0e99bf388
166 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, including calls to eval() and String.fromCharCode, which are commonly used for obfuscation and payload delivery. The heuristic 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' specifically indicates a stager pattern. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature. The primary attack pattern involves exploiting PDF vulnerabilities to run this script, which likely downloads and executes a second-stage payload.

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
90a25149b2bfea5999ffd219f1c30f78d1701852046779439507250e57353665
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627453 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).