Malicious PDF — malware analysis report

Static analysis result for SHA-256 fb84650c8dbbff58…

MALICIOUS

PDF

2.2 KB
MD5: 7c41579ce81960c97690203ef038a079 SHA-1: 56aae37c55737249de98977f2161cfeebbcf5869 SHA-256: fb84650c8dbbff58e10f42b890808b02e8252e0294669ae9ec7e7b745ecb58c3
286 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1071.001 Web Protocols

The PDF file contains obfuscated JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, PDF_EVAL, and PDF_UNESCAPE. Critical detections for CVE-2009_4324 and ClamAV signatures (Pdf.Exploit.Agent-36098, Js.Exploit.Shellcode-18) confirm malicious intent. The embedded JavaScript, particularly the use of eval() and unescape(), suggests it's designed to download and execute a secondary payload. The extracted JavaScript files, 'javascript_obj111611_000.js' and 'legacy_pdfkit_stage_000.js', further support this, with one being a deobfuscated version.

Heuristics 9

  • 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)
  • ClamAV: Pdf.Exploit.Agent-36098 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36098
  • 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)
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj111611_000.js
e1ab3bbf30605cecdce6db9d2556198626dbb178f7a4cb471a9436bb6e8bd92f
pdf-javascript-stream PDF /JS object 111611 at offset 0x7DB 462 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
ac6f56133406d5fb3312c752290e78e0113ad1b0e5b5e5cf47d30b1b7b8f2c58
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2433 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).