Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c98e399572eb0cf…

MALICIOUS

PDF

7.9 KB
MD5: a1776644cac95a83c1ac7fdb95692f2c SHA-1: 6d83f5b1123eee5415024849735b951da6df12a8 SHA-256: 4c98e399572eb0cf5c3a01ef6cc1c1de8131ef7e0e7c37eb3ad5e1fd2300452b
346 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 User Execution: Malicious Link T1204.002 User Execution: Malicious File

The PDF file contains embedded JavaScript that leverages multiple Adobe Reader vulnerabilities (CVE-2009-0927, CVE-2007-5659, CVE-2008-2992) to execute a malicious payload. The JavaScript is obfuscated and uses a custom Base64 decoder to unpack further layers. The heuristic firings and the detection of 'Js.Exploit.Shellcode-18' on an extracted artifact strongly indicate that this PDF is designed to exploit the user's reader application to download and execute a secondary stage.

Heuristics 10

  • Collab.getIcon — CVE-2009-0927 critical CVE exact CVE_2009_0927
    PDF JavaScript calls Collab.getIcon — CVE-2009-0927 is a stack buffer overflow in Adobe Reader triggered by Collab.getIcon() with a crafted argument. Allows arbitrary code execution. (identified after JavaScript deobfuscation)
  • 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)
  • util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992
    PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after JavaScript deobfuscation)
  • 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.
  • OpenAction trigger high PDF_OPENACTION
    PDF has an /OpenAction — code runs automatically when opened
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (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_obj0009_000.js
49c9d305f68b751498861d06daec7517cc6df9810ea67c41d1b1c928c6b3154c
pdf-javascript-stream PDF /JS object 9 at offset 0xD6 19916 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
custom_b64_stage_000.js
c7e395f30856dad97cdc453a03f80c0312bd10f3676e3581c974f5583fef2db4
deobfuscated-js custom Base64 decoded JavaScript layer 2 (PDF /JS object 9) at offset 0x436 10695 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 9 eval/decoder/string-building token(s).