Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9b6d0b76f79325c…

MALICIOUS

PDF

1.9 KB
MD5: 9fa3b963c18c53e5406d487fafb21e3a SHA-1: fab328579a3e7475455fe492dca00539a2d7b1e1 SHA-256: b9b6d0b76f79325cd7688005cec2d0eadadf1758ed89ba368aec77ff5e2d1f6a
188 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1027 Obfuscated Files or Information T1204.002 Malicious File

The PDF contains embedded JavaScript, which is heavily obfuscated using `eval()` and `unescape()` calls. Static analysis indicates this JavaScript is designed to download and execute a second-stage payload. The ML classifier and ClamAV detection strongly suggest malicious intent, specifically a PDF exploit.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • ClamAV: Pdf.Exploit.Agent-35930 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35930
  • 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.
  • 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
f23e505f155bfa9b9f356fa9fddf8d7fcafcc37fc2df3878e575e72c00c819d4
pdf-javascript-stream PDF /JS object 111611 at offset 0x66F 697 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
bd520a6870932e68e61058301aef20c1920270c9d06a8df3299c42534e2a18b1
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2834 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).