Malicious PDF — malware analysis report

Static analysis result for SHA-256 7167976f32ca372d…

MALICIOUS

PDF

33.5 KB
MD5: caf3d8f49ba8daba83b00551bf7ad4a6 SHA-1: 2d849fd5d16dfa013a3d85143026e800a44b0c87 SHA-256: 7167976f32ca372d8da19a3afeadd68eda7832d2f404c3c6746e2ece7f7fc743
220 Risk Score

Malware Insights

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

This PDF file contains obfuscated XFA JavaScript code that performs a heap spray, a common technique for exploiting vulnerabilities. The presence of 'PDF_XFA_HEAP_SPRAY' and 'ML_NYX_PDF_MALICIOUS' heuristics strongly indicates malicious intent. The embedded JavaScript stream is the primary artifact, likely serving as a dropper for further malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9922

Heuristics 9

  • XFA JavaScript heap-spray exploit code critical PDF_XFA_HEAP_SPRAY
    PDF contains XFA script content with heap-spray or shellcode-like JavaScript markers such as large encoded word sequences, util.pack, large arrays, or spray variable names. This is a weaponised Adobe Reader exploit pattern, not a normal interactive form.
  • ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • Hex-obfuscated structural name object high PDF_OBFUSCATED_NAME_OBJECT
    A structurally-dangerous PDF name (e.g. /OpenAction, /Launch, /AA, /EmbeddedFile, /SubmitForm) is written with #XX hex escapes to evade string-based scanners. Legitimate producers write these names literally; hex-encoding them is a deliberate obfuscation technique.
  • 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)
  • Embedded script payload in PDF stream low 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.
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PSSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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/1.0/
    • http://www.xfa.org/schema/xfa-template/2.4/
    • http://www.xfa.org/schema/xfa-data/1.0/
    • http://ns.adobe.com/xtd/
    • http://www.xfa.org/schema/xfa-form/2.8/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_000_off0000005f.js
5263bbb6198624ab3b53fe47f65ba4bfded491165d80535f33d341dfc2910a96		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5F 84792 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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