Malicious PDF — malware analysis report

Static analysis result for SHA-256 477d88965ebe2f2a…

MALICIOUS

PDF

15.3 KB
MD5: 33f5f0970338b9ad689372031c23b6bc SHA-1: b5fb0de333009091844ede8af1519da6a7ff92b2 SHA-256: 477d88965ebe2f2a22f4bbf257616ce783f6ebced82a9b4a3904fc0f551dd505
164 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript that utilizes eval() and unescape() functions, indicating obfuscation and likely malicious code execution. The ML classifier strongly flagged this PDF as malicious. The presence of a JavaScript stream and the use of eval() suggest the script attempts to download and execute a second-stage payload. The specific obfuscation techniques used in the script prevent a more detailed analysis of its exact function.

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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