Malicious PDF — malware analysis report

Static analysis result for SHA-256 2d4df1bcf4b14ee5…

MALICIOUS

PDF

21.5 KB
MD5: f168fb96000a6de543cb42879cbbdde2 SHA-1: 72fb316e0983cb0bcde69a70425a6d35181a2639 SHA-256: 2d4df1bcf4b14ee5542ca02100b1485ced1731b22865f320cc6e3aaf879a3964
108 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1204.002 Malicious File

The PDF file contains embedded JavaScript and triggers CVE-2009-4324 via the media.newPlayer annotation. The embedded JavaScript, specifically 'legacy_pdfkit_stage_000.js', is designed to download and execute a second-stage payload. The ML classifier strongly indicates malicious intent. The reconstructed JavaScript string 'app["vie"+"werTy"+app.doc.URL[3]+"e"][1]' suggests an attempt to interact with the browser environment, likely to facilitate the download.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 4

  • media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324
    PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
  • 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.
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0008_000.js
5861afc4eeaf149384a77d9e7e67f75382d5b774633805f533203129673f224d		 pdf-javascript-stream PDF /JS object 8 at offset 0x1E7 2221 bytes
legacy_pdfkit_stage_000.js
630bbd87d4c991442612bbfc5d0e64a58d98100212c3f8e897f80b45684ffd16		 deobfuscated-js repeated-marker hex decoded JavaScript at offset 0xAC8 1262 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
42025b552c7960b53abcd8cd732b01c8d109eccfdfefc352b9826c4d5807d414		 deobfuscated-js cross-stage annotation API aliases at offset 0x1E7 81 bytes

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