Malicious PDF — malware analysis report

Static analysis result for SHA-256 5ff2681f16386b90…

MALICIOUS

PDF

3.5 KB Created: 2009-04-23 22:10:54 Authoring application: Scribus 1.3.3.12 (via Scribus PDF Library 1.3.3.12)
MD5: 64876f9f8448dd81ac761d392a555c7e SHA-1: 5a9ab49a67285020715884595f0d9720d32b70da SHA-256: 5ff2681f16386b902b2547b8ef5d8050d4e2749b535c7537cb44e3dc41fbac28
276 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript that uses eval() and String.fromCharCode() for obfuscation. The deobfuscated JavaScript is also heavily obfuscated, indicating an attempt to hide malicious functionality. The critical heuristic firings for PDF JavaScript exploit clusters and ClamAV detections strongly suggest this PDF is designed to exploit vulnerabilities and download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • 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-35835 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35835
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0013_000.js
0dca4bae4a0f0c1ed0a2cbcf405a8773344f38272eab1975223f4d2c25d19ae1
pdf-javascript-stream PDF /JS object 13 at offset 0x3CE 7151 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35835
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
e66c7ef134b960063bdeff3550d5b0083ebbb724cceb13a48ec4f8cb0ac587ea
deobfuscated-js PDF JavaScript deobfuscation pass 16504 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35835
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).