Malicious PDF — malware analysis report

Static analysis result for SHA-256 af28d7f8c7e7440f…

MALICIOUS

PDF

2.1 KB
MD5: d908a8241b1f45366633dc6b290d30bf SHA-1: 022b1d1abda6b2029318af97c77020251dece104 SHA-256: af28d7f8c7e7440f5f234d7cca54adacbd2d987c167b596dad2ac4a1221cdd31
136 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.007 JavaScript

The PDF contains embedded JavaScript, which is heavily obfuscated using eval() and unescape() calls. The ML classifier strongly indicates maliciousness. The extracted JavaScript file, 'javascript_obj111611_000.js', is suspicious and likely responsible for downloading and executing a secondary payload. The presence of JavaScript actions and streams within the PDF points to a common delivery technique for malware.

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 0x75B 332 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).