Malicious PDF — malware analysis report

Static analysis result for SHA-256 626f2250c34b860d…

MALICIOUS

PDF

132.6 KB Created: 2008-04-23 16:42:36 +08:00 Authoring application: Acrobat PDFMaker 6.0 for Word (via Acrobat Distiller 6.0 (Windows))
MD5: 6d27bb824b845cd67e5fe63f0a8b884f SHA-1: 0c8fde1c5092b653489959fbd76274f9aebcbaee SHA-256: 626f2250c34b860d0a3109eddab5c1cbbd6bf1809b5c10249393f78889f3dcc9
446 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript T1105 Ingress Tool Transfer

This PDF file exploits CVE-2007-5659 (Collab.collectEmailInfo) via embedded JavaScript to deliver a Windows executable payload. The JavaScript code, found in multiple streams, is heavily obfuscated but appears to be responsible for downloading and executing the embedded PE file. The presence of an embedded executable and exploit-related heuristics strongly indicates a malicious intent to compromise the user's system.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 13

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (matched in decompressed stream)
  • 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.
  • Embedded Windows executable payload in PDF stream critical PDF_EMBEDDED_PE_PAYLOAD
    PDF stream bytes contain an embedded Windows executable with a verified PE header. Exploit chains often hide droppers inside ordinary streams rather than standard /EmbeddedFile attachments.
  • Secondary embedded PDF body has suspicious static findings critical POLYGLOT_CHILD_PDF_STATIC_TRIAGE
    A valid PDF body was found at a nonzero offset inside another container and its carved contents matched PDF exploit or lure heuristics. This catches polyglots where the top-level magic routes to ZIP/OLE while a PDF reader or downstream parser opens the hidden PDF payload.
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • 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
  • 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://www.w3.org/1999/xhtml
    • http://www.xfa.org/schema/xfa-data/1.0/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/iX/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/pdfx/1.3/
    • http://ns.adobe.com/photoshop/1.0/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ctfmon.exe
48e449f1dbb36c155ae86f1f9556fa905354655ba2d3a3b3188608684d5423c1		 pdf-embedded-file PDF EmbeddedFile object 29 at offset 0x1063 15228 bytes
javascript_obj0026_000.js
adb06aedf7bc478acf6ab546b55cd41f86afa52b0b8118772f10b011b346b302		 pdf-javascript-stream PDF /JS object 26 at offset 0xA98 3428 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 17 eval/decoder/string-building token(s).
javascript_obj0026_001.js
a10001506b3bca6aae51e7b5a754c72956eb5e4a82ce7fe201cabccde9646905		 pdf-javascript-stream PDF /JS object 26 at offset 0xACF 3373 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).
generic_stage_recovery_000.js
1489c0950d0ea36086cab9c9e07fc1f70b5182bb65246dd066f5dbae69d5d6b2		 deobfuscated-js generic stage recovery percent-decode from JavaScript object 26 at offset 0xA98 3414 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 17 eval/decoder/string-building token(s).
generic_stage_recovery_001.js
31c85ca6c6a5a7f4e18094c1371c12ed9ac555c021c7a659995d42a9aef1ff61		 deobfuscated-js generic stage recovery percent-decode from combined JavaScript objects at offset 0xA98 6788 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 33 eval/decoder/string-building token(s).
combined_document_js_000.js
58f59798c1f0bb0edf6cd6f35e77a1ae9fbbb1cc658f6157930360008b5341d2		 deobfuscated-js combined document JavaScript streams at offset 0xA98 6802 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 33 eval/decoder/string-building token(s).
polyglot_child_pdf_off0001be36.pdf
a895eab1e194ba790c3fb1fb040a6115b1adf853870a3a20e8439bd07d059e13		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x1BE36 21599 bytes

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