Malicious PDF / .TXT — malware analysis report

Static analysis result for SHA-256 b91c646f47e1fd8d…

MALICIOUS

PDF / .TXT

12.0 KB
MD5: 8bf39c7644900cdc4d1c79a4f4cec557 SHA-1: aef8e5a641e438edb4aef6f351797bf3ea1cea34 SHA-256: b91c646f47e1fd8d15020dffabbc8876f9e1880ae02f02e154cc62ed603249b2
146 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link

The PDF file contains embedded JavaScript that leverages the CVE-2007-5659 vulnerability, specifically targeting the Collab.collectEmailInfo function. Static analysis indicates that this JavaScript is responsible for downloading and executing a second-stage payload, as evidenced by the deobfuscated JavaScript files legacy_pdfkit_stage_000.js and legacy_pdfkit_stage_001.js. The presence of these deobfuscated scripts and the critical heuristic firing for CVE-2007-5659 strongly suggest a malicious exploit attempt.

Heuristics 6

  • 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. (identified after JavaScript deobfuscation)
  • ClamAV: Pdf.Exploit.Agent-35903 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35903
  • 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.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed 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.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
860eae5f96eb426380281c575a089242b50523bbb4bbb8dd765e582cd9c07d2e
pdf-javascript-stream PDF /JS object 7 at offset 0x19D 294 bytes
legacy_pdfkit_stage_000.js
f7d47f05bb2d98cc7416c6944b8f6730e9868726c4e630644e7e8b54f81e796c
deobfuscated-js z-percent hex-pair decoded JavaScript at offset 0x2E8 5087 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
9d992f9512244755efd9d216b0401ca868efa80bebc6d625d1f7011f5b497e79
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2E8 12184 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).