Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8a1a75a5ecaa459…

MALICIOUS

PDF

118.5 KB
MD5: 4d354bdd2234b7f4c93edb864169e541 SHA-1: 3fe6d595e1be5728c5ce7986d86d092ed43b1a2d SHA-256: b8a1a75a5ecaa459eedf297370a94f2b9e444e84ae9add36a8a75937768dbba8
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/Shell Script Execution: JavaScript T1204.002 Malicious File: User Execution: Malicious File

The PDF contains embedded JavaScript, including a large, obfuscated eval stager. This suggests the script is designed to download and execute a second-stage payload. ClamAV detection as 'Pdf.Exploit.Agent-36086' further supports its malicious nature. The document body was unreadable, so the rationale is based on the script and heuristics.

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
dc0144a112f109c24e6c0137fb3457e5974bd6e4dfe09f95b0a1dcbb9b6fcfde
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627009 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).