Malicious PDF — malware analysis report

Static analysis result for SHA-256 21143215bf15037d…

MALICIOUS

PDF

2.2 KB
MD5: 2fbaba295f443551223564e42d3dc751 SHA-1: 633674d523ca73864ccbe96b72785008327a548e SHA-256: 21143215bf15037d6857abe5f8a0a57919ac388e1c5effce4a8eb01ca41476c7
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.007 JavaScript

The PDF file contains embedded JavaScript, which is heavily obfuscated using `eval()` and `unescape()` functions. This obfuscation suggests an attempt to hide malicious code execution. The presence of `String.fromCharCode` further indicates dynamic code generation. ClamAV detection as 'Pdf.Exploit.Agent-36082' strongly suggests exploitation of a known PDF vulnerability to achieve arbitrary code execution, likely to download and run a second-stage payload.

Heuristics 7

  • ClamAV: Pdf.Exploit.Agent-36082 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36082
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • 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_obj111611_000.js
772da696bdb365f3f1eb4ea6af881baad391be62f3591b19f2f9827fcc4c9b53
pdf-javascript-stream PDF /JS object 111611 at offset 0x7E3 479 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
82daeb2b491f3fb517221c19a9146c3494eb20af4c03e8c69528337e2977f4f5
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2828 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).