Malicious PDF — malware analysis report

Static analysis result for SHA-256 99a6c907f5b84f05…

MALICIOUS

PDF

24.6 KB
MD5: 261fb282aa0ba4ba22c884f39bd3d523 SHA-1: 53bad0943c45763a63a2bc346944a74930aeb5e7 SHA-256: 99a6c907f5b84f055d5f211be3c7be5c9e46a9df8c83ab9d82f0c5205278b789
158 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.007 JavaScript T1566.002 Spearphishing Attachment

The PDF contains embedded scripts and XFA forms, indicated by multiple high-severity heuristics including PDF_UNESCAPE, PDF_XFA_SCRIPT, and ML_NYX_PDF_MALICIOUS. The presence of an embedded file and script payload suggests it's designed to deliver a secondary malicious payload. The ML classifier output of 0.999995 strongly indicates malicious intent. The embedded URLs are not directly actionable for exploitation but are part of the document's structure.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • XFA form contains risky executable script high CVE related PDF_XFA_SCRIPT
    PDF embeds an XFA form whose script block contains exploit, submission/launch, or shell-execution primitives. Ordinary LiveCycle print/update scripts are left as generic XFA/JS signals unless stronger behavior is present.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits
  • Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • 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.
  • 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/xfa-template/2.5/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin
0b7c7e556c73e413c77a984bdb89d68f7627b9e506e50bfc177b966021631102		 pdf-embedded-file PDF EmbeddedFile object 8 at offset 0xC6 24445 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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