Malicious PDF — malware analysis report

Static analysis result for SHA-256 236009dfba2cb471…

MALICIOUS

PDF

25.0 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode
MD5: ffa619d190aed440fc6b9c51a565260b SHA-1: da221f139be44ea5afac0899d372496930cc9b13 SHA-256: 236009dfba2cb4718ba2fca640de29e275dfe08be5b6543e0b5f8726c9402664
64 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, identified by the 'PDF_JAVASCRIPT' and 'PDF_JS' heuristics. The 'PDF_METADATA_EVAL_STAGER' heuristic indicates that the JavaScript is used to decode and execute further code, likely from the metadata itself. The use of 'String.fromCharCode' suggests obfuscation to hide the malicious payload. The primary attack pattern involves leveraging JavaScript within the PDF structure to achieve code execution, a common technique for delivering secondary malware.

Heuristics 4

  • PDF metadata JavaScript eval stager high PDF_METADATA_EVAL_STAGER
    PDF JavaScript reads document metadata fields such as title, subject, or producer, decodes character data with parseInt/String.fromCharCode style helpers, and evals the recovered stage. This is a high-signal exploit-kit staging pattern.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0001_000.js
6a04dbb6bbf6a9337548d1e535c203f800df6a4a46339ec3f26ecf12fea9beae
pdf-javascript-stream PDF /JS object 1 at offset 0x6156 452 bytes