Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c1bc230d35e887b…

MALICIOUS

PDF

7.8 KB
MD5: e01e1cb6553a04b884a0eb79bf525c55 SHA-1: 28495ed3e11471efdd7ff7eec5c0732f1d4e0b04 SHA-256: 4c1bc230d35e887b96d92d8bd61d53c47d46bc498adeeb934a0bc90c43af7681
346 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1204.002 Malicious File: Malicious Attachment T1059 Command and Scripting Interpreter T1059.001 Command and Scripting Interpreter: PowerShell T1059.007 Command and Scripting Interpreter: JavaScript

The PDF file contains embedded JavaScript that is heavily obfuscated and utilizes custom Base64 decoding. This script is designed to exploit known Adobe Reader vulnerabilities, specifically CVE-2009-0927, CVE-2007-5659, and CVE-2008-2992, to achieve code execution. The primary intent is to download and execute a second-stage payload, as indicated by the ClamAV detection of 'Js.Exploit.Shellcode-18'.

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
22f89170c24ec065d30dcc25604e97b1f250049824fcd9af0152330b42505677
pdf-javascript-stream PDF /JS object 9 at offset 0xD6 19572 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
1c9ec4d3fc28699843b803da1edc235513e5173d0a20ee575f0ef492d417fc08
deobfuscated-js custom Base64 decoded JavaScript layer 2 (PDF /JS object 9) at offset 0x436 10503 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 9 eval/decoder/string-building token(s).