Malicious PDF — malware analysis report

Static analysis result for SHA-256 e9feef2461a26f56…

MALICIOUS

PDF

2.1 KB
MD5: e7522243ed4244a30540a82ad10f0f4a SHA-1: 905c1dfd8ca3b5c7cc70e791bb7c77bd06c20273 SHA-256: e9feef2461a26f56d64f0a604346a0ff78904cbe800884ab6fedd176ee9ec85a
136 Risk Score

Malware Insights

MITRE ATT&CK
T1027 Obfuscated Files or Information

The PDF file contains embedded JavaScript, which is heavily obfuscated using eval() and unescape() functions. The ML classifier strongly indicates maliciousness. The embedded JavaScript file, 'javascript_obj111611_000.js', is the primary artifact, suggesting it's responsible for the malicious payload delivery. The obfuscation techniques used point towards an attempt to hide the script's true functionality, likely to download and execute a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj111611_000.js
9864171cc4152f5d3e5671809dd40cebe1cf9319d0b8bfb0abd003cff50482db
pdf-javascript-stream PDF /JS object 111611 at offset 0x75E 332 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).