Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5a074bf841d0ef2…

MALICIOUS

PDF

2.3 KB
MD5: 0b07c61cdc9139dea4dae4566b7bedd7 SHA-1: b52bc31e9812a949376bff044c4eae2adcc9c4e9 SHA-256: b5a074bf841d0ef24ce6a729818f52717db0d60c2d9d5c548541cca6cbad2540
226 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.001 Malicious Link T1204.002 Malicious File

This PDF file contains embedded JavaScript that is obfuscated using `unescape()` and `String.fromCharCode()`. The critical heuristic `CVE_2007_5659` indicates the use of the `Collab.collectEmailInfo` method, a known exploit vector for older Adobe Reader versions. The JavaScript is likely designed to download and execute a second-stage payload, as suggested by the presence of deobfuscated JavaScript files. The file is detected by ClamAV as `Pdf.Exploit.Agent-36098`.

Heuristics 8

  • 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-36098 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36098
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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.
  • 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj111611_000.js
e1ab3bbf30605cecdce6db9d2556198626dbb178f7a4cb471a9436bb6e8bd92f
pdf-javascript-stream PDF /JS object 111611 at offset 0x801 462 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
bef88e819a4de935c8f07cfb1d37f2c4623e5a9ad48ccdbe617daba6be90f8d8
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2652 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).