Malicious PDF — malware analysis report

Static analysis result for SHA-256 11cb7e4d44acd77d…

MALICIOUS

PDF

6.7 KB Created: 2009-11-17 23:22:12 Authoring application: Scribus 1.3.5svn (via Scribus PDF Library 1.3.5svn)
MD5: b1dcf778dedcc387688f391aac6045f9 SHA-1: 011566dea36212d4923d71f3ed5e76e9baeb992a SHA-256: 11cb7e4d44acd77df01b8b8333cb6bdd4b7b2b0e993940c0bb2047f184648e4c
216 Risk Score

Malware Insights

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

This PDF file contains embedded JavaScript that utilizes unescape and String.fromCharCode functions, indicating obfuscation and an attempt to exploit a vulnerability. The critical PDF JavaScript exploit cluster heuristic and ClamAV detection strongly suggest malicious intent. The JavaScript is likely designed to download and execute a second-stage payload, a common technique for malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • 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.
  • ClamAV: Pdf.Exploit.Agent-3856 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-3856
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0016_001.js
42f9fddaabb53306b65a2808e8f17f8bca4114d586c677276c1d884ecfef0eef
pdf-javascript-stream PDF /JS object 16 at offset 0xC9A 12459 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).