Malicious PDF — malware analysis report

Static analysis result for SHA-256 03eb4de886bb22c5…

MALICIOUS

PDF

16.4 KB
MD5: 79d5f1894b54958a47324949bb93f249 SHA-1: 792608eaf4a14a1cd604d7a5e38fcb2d8958cb86 SHA-256: 03eb4de886bb22c545d1338ec11a1c97dd9aaccdb037783a80182a2cb8905215
118 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript that is obfuscated using String.fromCharCode and string concatenation. The script appears to be designed to download and execute a second-stage payload from a remote source, indicated by the heuristic 'PDF JavaScript exploit cluster'. The ML classifier strongly flags this PDF as malicious. No specific family could be identified due to the obfuscation and lack of clear indicators.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 6

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0013_000.js
9fd87306e37a04c361ea1b68a1cf4474b7a018e2270929a8c382cd129d8fc406		 pdf-javascript-stream PDF /JS object 13 at offset 0x2FE 566 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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