Malicious PDF — malware analysis report

Static analysis result for SHA-256 664111e928cf8fcf…

MALICIOUS

PDF

1005.3 KB Created: 2008-03-20 15:51:33 +08:00 Authoring application: Acrobat 编辑器 8.0 (via Adobe Acrobat 8.1.0)
MD5: 5f8fc3786492fed3cc2d647a532f2e8a SHA-1: 2d820795db828d9a06930959a35bc80a24768ccc SHA-256: 664111e928cf8fcf720f7ec50fc9644a22f963324eef76da49cc130ef7e49a19
340 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that leverages the Collab.collectEmailInfo method to exploit CVE-2007-5659. This exploit is designed to download and execute a secondary payload, as indicated by the critical heuristic firings and the ClamAV detection of a dropper. The JavaScript code itself is heavily obfuscated, but the exploit target is clear.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 11

  • 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.
  • ClamAV: Win.Trojan.Dropper-82 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Dropper-82
  • 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
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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/1999/02/22-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/pdf/1.3/

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
txt
a036e7f7193820d54e561d5a9b2dbd5c7d7165694977140db8b60c42151fcabb		 pdf-embedded-file PDF EmbeddedFile object 1 at offset 0xF90 2041 bytes
javascript_obj0028_000.js
b93eb231ef1cebd6f384bec36f1081cd8e61c8a383b8c740137a5a97cca69b28		 pdf-javascript-stream PDF /JS object 28 at offset 0x6FE 4617 bytes
Detection
ClamAV: Win.Trojan.Dropper-82
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).
javascript_obj0033_001.js
53c727718aed325cf4543f06656679b4e18980941e29aca21f3c369fcbc96f10		 pdf-javascript-stream PDF /JS object 33 at offset 0xF9EA1 4620 bytes
Detection
ClamAV: Win.Trojan.Dropper-82
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).
combined_document_js_000.js
fd3fa6255a38fcb108745b9a6e9adad0807d47a59ff29db9384e63eb23326ade		 deobfuscated-js combined document JavaScript streams at offset 0x6FE 9238 bytes
Detection
ClamAV: Win.Trojan.Dropper-82
Obfuscation or payload: likely
Carved artifact contains 32 eval/decoder/string-building token(s).

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