Malicious PDF — malware analysis report

Static analysis result for SHA-256 f70a1fd0742f72a3…

MALICIOUS

PDF

2.3 KB
MD5: cc01cb8468bf67839999b3787c43ee2d SHA-1: 703bbc2869144457b3dfa1f562094fb5aeb78c98 SHA-256: f70a1fd0742f72a3e65907ddf0a7f3bce2b30d2f74a78c843a5d38b7f17700b7
226 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/Shell Scripting: JavaScript T1204.001 Malicious Link: Malicious Link T1059.003 Command and Scripting Interpreter: Windows Command Shell

The PDF file contains embedded JavaScript that utilizes the 'Collab.collectEmailInfo' method, a known indicator for the CVE-2007-5659 vulnerability. The JavaScript is obfuscated using 'eval()' and 'unescape()', and further processed by 'String.fromCharCode()'. This indicates the sample attempts to exploit this vulnerability to download and execute a second-stage payload. The presence of multiple JavaScript streams and the ClamAV detection as 'Pdf.Exploit.Agent-36082' reinforce this assessment.

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-36082 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36082
  • 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
772da696bdb365f3f1eb4ea6af881baad391be62f3591b19f2f9827fcc4c9b53
pdf-javascript-stream PDF /JS object 111611 at offset 0x84A 479 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
3c84e21c550ebff30c48b9d80df37430f474df20f872981054405a28dc17a699
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2640 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).