Malicious PDF — malware analysis report

Static analysis result for SHA-256 1663092522ccca09…

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: 1cd533addded216557b888244672e078 SHA-1: a90f86eff32d1f675f967db91f0bf76e055109fb SHA-256: 1663092522ccca094cbe96106f86a39ccf627144db8b3d0ba89fea2ca46d2d81
156 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 utilizes unescape() and String.fromCharCode functions, indicating an attempt to obfuscate malicious code. This script is part of a known exploit cluster targeting PDF viewers. The primary function of the script is to download and execute a second-stage payload, which is a common technique for delivering malware.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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.
  • 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
057dd1858428f7bbed04a4f8668e5a315fd257212754b858424ae93685c1e4ba
pdf-javascript-stream PDF /JS object 16 at offset 0xC9A 12549 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).