Malicious PDF — malware analysis report

Static analysis result for SHA-256 bd5b8566184842ff…

MALICIOUS

PDF

15.7 KB
MD5: deb2c82dc677762494d8ab019e408ab7 SHA-1: 441ee2c5ab54c15896d836abb68e2143726b1d19 SHA-256: bd5b8566184842ff9806f75a61e80bb658138c322246b3f8eff8b2369ffa41cd
196 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript that utilizes `eval()` and `String.fromCharCode()`, indicating obfuscated code execution. High-confidence heuristics and ML classification flag this as malicious. ClamAV identifies it as 'Pdf.Exploit.Agent-36086', suggesting it's a known exploit leveraging PDF vulnerabilities. The primary function appears to be the execution of this JavaScript, which is a common stager for downloading further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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
11116331fdf927e5b117db0b9de05cfa3bfd2aa92294ee924887657b2c13edb6
pdf-javascript-stream PDF /JS object 6 at offset 0x143 424927 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).