Malicious PDF — malware analysis report

Static analysis result for SHA-256 56667c12a8a10cfa…

MALICIOUS

PDF

15.7 KB
MD5: 79f31a4fe60b75cd13e3178c93be5363 SHA-1: de85fece2179561019eea10ba2ea97b66dc93811 SHA-256: 56667c12a8a10cfa68bc3e8d6a9425a5dfb5b20e23c7bc3ec984e21d14dc437d
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.002 Malicious File

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_JS_LARGE_COMMENT_PADDED_EVAL. The presence of eval() calls and String.fromCharCode suggests obfuscation and dynamic code execution. The ClamAV detection of 'Pdf.Exploit.Agent-36086' strongly suggests this is a known exploit. The embedded JavaScript is likely designed to download and execute a secondary payload, a common technique for initial access.

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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
d91abcd1e2a8967aae3f28126f7ab3c9fd9baad4d15a3455ad4ee0572cb2729b
pdf-javascript-stream PDF /JS object 6 at offset 0x143 425566 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).
legacy_pdfkit_stage_000.js
64ab44b35d6b2a7130768bb29200278a6fbc4983353ab6c9af9da227bb5e6625
deobfuscated-js double percent-decoded annotation JavaScript at offset 0x143 262144 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 667 long base64-like blob(s).