Malicious PDF — malware analysis report

Static analysis result for SHA-256 9c176d4249e9a267…

MALICIOUS

PDF

2.4 KB
MD5: d527d596f3890fe095ea0d3ef5ad4882 SHA-1: bc236c399f85f2686645a7859466e3d14daae820 SHA-256: 9c176d4249e9a26759549de2d1ab4ff762485be636e4e211ccfc386bea659d2a
166 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious File Execution: Exploitation for Public-Facing Application

The PDF file contains embedded JavaScript that utilizes the `Collab.collectEmailInfo` method, indicating exploitation of CVE-2007-5659. The JavaScript is obfuscated using `eval()` and `unescape()`, and further processed by `String.fromCharCode()`. This script is designed to download and execute a second-stage payload. The presence of multiple JavaScript streams and obfuscation techniques points towards a downloader or dropper functionality.

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)
  • 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
e7d1232c16a6e584ebcad6ed89ed39659361935894de0b1df6aee2e4fe16ce04
pdf-javascript-stream PDF /JS object 111611 at offset 0x859 478 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
01ab7b67f90f3d6ef0da736e152e2dbde0be4326d81585ab1db118db84bc411f
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2658 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).