Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1121dcb3bcce515…

MALICIOUS

PDF

114.7 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: b81db2148e3b98f0b743f0a103c638a9 SHA-1: 7bd001b7fb586dbfd2d24f183e065ad756b294a7 SHA-256: b1121dcb3bcce5152709cd72b72d8980eaddd0d31d6c52752722e1a310aedae2
466 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File

This PDF document exploits CVE-2007-5659 (Collab.collectEmailInfo) and other PDF JavaScript vulnerabilities to deliver an embedded Windows executable. The embedded JavaScript, specifically the 'start' function, appears to be heavily obfuscated but is designed to trigger the exploit and likely download additional payloads. The presence of an embedded PE file and multiple critical heuristic firings strongly indicate a malicious intent to compromise the user's system.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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: Pdf.Exploit.Agent-35909 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35909
  • 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)
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ctfmon.exe
48e449f1dbb36c155ae86f1f9556fa905354655ba2d3a3b3188608684d5423c1		 pdf-embedded-file PDF EmbeddedFile object 29 at offset 0x1059 15228 bytes
javascript_obj0026_000.js
121c6b30fa6870a78cfdf1b1aba8fed5d3071efaf26ad347680c0b9d339f0e69		 pdf-javascript-stream PDF /JS object 26 at offset 0xA98 3373 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).
polyglot_child_pdf_off00017688.pdf
7150260cd8d7bde823e4adea64d962588de00e51b67f5db80e14071097ec8bfb		 polyglot-child-pdf Secondary PDF body inside pdf container at offset 0x17688 21589 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35909
Obfuscation or payload: unlikely

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