PDF malware analysis — malicious · 98f3874567c09bea

MALICIOUS

PDF

8.0 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode

MD5: 129eae9807bfc66667b1e971afa3f19f SHA-1: cabe9717185b29393ede74cecdc7228f98f2b425 SHA-256: 98f3874567c09beace468b68852d5b5a02e3deb56efae041f84238a8d4775092

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious File: Malicious File

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream utilizes `String.fromCharCode` and an `eval()` call, suggesting obfuscation and dynamic code execution. The ML classifier strongly flags this PDF as malicious. The primary attack pattern involves leveraging JavaScript to execute arbitrary code, likely to download and run a secondary payload. No specific family could be identified.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 5

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.
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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0001_000.js` `c0ea098f32774b8e7e24aeaddf15c539ceb5fc421f69d34d6cff710accfb5234`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	952 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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