PDF malware analysis — malicious · d910ebb97c4b220d

MALICIOUS

PDF

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

MD5: 0db31f2216eaa0f95f90eda8830228c0 SHA-1: 1a3fcf8c2ca61652533eda961dfb15a54d4b11d9 SHA-256: d910ebb97c4b220da48d2912e4e99c2b6da5b2c41fe0663e306b5a923d4e9c8b

98 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell T1059.007 Command and Scripting Interpreter: JavaScript/TypeScript

The PDF contains embedded JavaScript, flagged by multiple heuristics including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The ML classifier also strongly indicates maliciousness. The JavaScript stream, named javascript_obj0001_000.js, is obfuscated and likely responsible for downloading and executing a secondary payload. The use of String.fromCharCode and eval() within the JavaScript points to a common technique for evading static analysis.

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` `7405dc34f05e9fcdc285bf9d269e2999f33d3617fcd7aaf8e5129ea2cf9e1cdc`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	511 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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