Malicious PDF — malware analysis report

Static analysis result for SHA-256 5d974b6ede7b6286…

MALICIOUS

PDF

29.8 KB
MD5: d240b086b262a15417b560bc2093d5cc SHA-1: de40712edfd6a08fe272e4719a94ccc55fc0ac36 SHA-256: 5d974b6ede7b6286619201e1fcb315e3bd696e0a11b9457909816a32c7d35866
174 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript and a Flash object (test.swf), indicating an attempt to exploit vulnerabilities. The JavaScript uses String.fromCharCode to obfuscate its content, a common technique for malicious scripts. The presence of PDF_JS_EXPLOIT_CLUSTER and ML_NYX_PDF_MALICIOUS heuristics strongly suggests malicious intent. The script likely downloads and executes a second-stage payload from one of the unknown reputation URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • 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.
  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector
  • 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.
  • 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. (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://code.flashdynamix.com/AES/aes-decrypt.php
    • http://code.flashdynamix.com/AES/aes-encrypt.php
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/
    • 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/
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://adobe.com/AS3/2006/builtin

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
test.swf
4d4d42d908c48737d0cbe1f33c14f197803950e6ff47f9c0f13e1d51a231494d		 pdf-embedded-file PDF EmbeddedFile object 16 at offset 0x8CC 53991 bytes
javascript_obj0006_000.js
218cce5bfaac249b574d6f395877d5cd81b5409caef0875d99edc69114a4219c		 pdf-javascript-stream PDF /JS object 6 at offset 0x106 11498 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 239 eval/decoder/string-building token(s).

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