Malicious PDF — malware analysis report

Static analysis result for SHA-256 10046f147019692d…

MALICIOUS

PDF

18.0 KB Created: 2011-72-51 03:25:00
MD5: aa43ddabd32be49cd6220d8a286bf21b SHA-1: 58eb7e34a236f9a24c888a461914f5ebaf6ff282 SHA-256: 10046f147019692df09f54e9d444b0cc95872eb30ed986eb4216fc947042e1ab
116 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that is heavily obfuscated using string concatenation and function calls. Heuristics indicate this JavaScript is part of an exploit cluster, likely designed to download and execute a secondary payload. The ML classifier strongly flags this PDF as malicious, supporting the exploit and download-execute pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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.
  • 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_obj0001_000.js
b629ce97b78c95befe0a25059bf0de3215139c8f6cca984c467b4849a5df9f92
pdf-javascript-stream PDF /JS object 1 at offset 0x4607 337 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).