Malicious PDF — malware analysis report

Static analysis result for SHA-256 bbdd3d8baa0c661a…

MALICIOUS

PDF

118.7 KB
MD5: c884cdce398b68bb0d6e6d409fe6fd68 SHA-1: e3097244eb8811fbadd76d2e4ba1e79bbf5f7eff SHA-256: bbdd3d8baa0c661aa60bd5b6f12b5c7a841f684ada2d2842409e52844a94ac85
166 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript that utilizes eval() and String.fromCharCode, indicating obfuscated code execution. The heuristic 'PDF_JS_LARGE_COMMENT_PADDED_EVAL' strongly suggests a stager designed to download and execute a second-stage payload. ClamAV detection as 'Pdf.Exploit.Agent-36086' further confirms its malicious nature, pointing towards an exploit delivery mechanism.

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
f4ebcb2ee5f5a4329cb53cd5b9fb24d7d8c5329891466bbd190f3903c43d733c
pdf-javascript-stream PDF /JS object 6 at offset 0x143 626967 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).