Malicious PDF — malware analysis report

Static analysis result for SHA-256 c672fca4d5dc9c7f…

MALICIOUS

PDF

13.2 KB
MD5: 56634065660a73c41cc470ac2a1b914f SHA-1: 989003757dd50850670c505db4ce946efaa07f50 SHA-256: c672fca4d5dc9c7fe13cef52d6a99d96cb74682f3e806350889865ad580c38fb
216 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link T1071.001 Web Protocols

The PDF file contains obfuscated JavaScript that utilizes the `Collab.collectEmailInfo` method to exploit CVE-2007-5659 in Adobe Reader. The JavaScript is further obfuscated using binary-XOR encoding and `String.fromCharCode`. The primary goal appears to be the execution of a second-stage payload, as indicated by the stager heuristic. No specific family could be identified, but the exploit and stager mechanism are clear.

Heuristics 7

  • 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: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • Binary-XOR JavaScript stager high PDF_BINARY_XOR_JS_STAGER
    PDF JavaScript stores viewer-version payload branches as long binary digit strings, XORs each bit pair, converts 8-bit chunks with String.fromCharCode, and evals the recovered exploit stage.
  • String.fromCharCode medium PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically (matched inside decoded stream)
  • Suspicious extracted artifact medium 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.
  • 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0049_000.js
b56cb10bbb1992f24250360f2629919401a25ab7879367425ebdc4128626cbd2
pdf-javascript-stream PDF /JS object 49 at offset 0xA 78556 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 6 long base64-like blob(s).
binary_xor_stage_000.js
df4392da5ae75b6a53ee5813cb8c1a374e11da6cfd2c80dec2252b2f535f3c94
deobfuscated-js binary-XOR decoded JavaScript at offset 0x3F8 1312 bytes