Malicious PDF — malware analysis report

Static analysis result for SHA-256 fea1c86d987f97cb…

MALICIOUS

PDF

15.3 KB
MD5: f90a2d221601a04265fdb87108a3543c SHA-1: b0cc3b0fd8287cd5be5d939203e7560d2200d301 SHA-256: fea1c86d987f97cbda7099d1f1f23d4b61157e035d0ca2419c6c07b3fa02e684
164 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1027 Obfuscated Files or Information T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript that utilizes `eval()` and `unescape()` functions, indicating obfuscation and potential malicious code execution. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript is likely responsible for downloading and executing a second-stage payload, though the exact mechanism is obscured. The presence of XFA form elements and JavaScript actions points towards a sophisticated attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 9

  • 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)
  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
  • 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.
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0012_000.js
09de78b7de291aa3ddc78e96475725267630bf326894c1fb6b9aff709f8aec31		 pdf-javascript-stream PDF /JS object 12 at offset 0x1BF2 363 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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