Malicious PDF — malware analysis report

Static analysis result for SHA-256 5a51640fdc5262df…

MALICIOUS

PDF

59.5 KB Created: 2012-07-31 22:05:59 +04:00 Authoring application: Adobe Acrobat 7.0 (via Adobe Acrobat 7.0 Image Conversion Plug-in)
MD5: c11820e8a4fe77cc7d1a0f91c433e39b SHA-1: 725e1f785283d1f0313ca50b51a4a21c9aaade06 SHA-256: 5a51640fdc5262df50da5e65a9be27cf0aa3d3f3f807cc8016ebb867e5c42b58
118 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. This script is designed to decode and execute a payload, likely for further exploitation or malware delivery. The ML classifier strongly indicates maliciousness, and the presence of JavaScript exploit cluster heuristics further supports this. The script's primary function appears to be displaying an alert box with a decoded string, which is a common technique for delivering malicious content or commands.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • 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. (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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0106_000.js
7a49368c0379a2fbcd93d4e6b6998141ccbdfb6cba7bf8f7619a23f245e66067		 pdf-javascript-stream PDF /JS object 106 at offset 0xEA2E 1560 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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