PDF malware analysis — malicious · 286df3457f8c4c99

MALICIOUS

PDF

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

MD5: b4e5f12ed5dce41115e65a48e1ecc12d SHA-1: e23a5f304a6bcb5b3f1cad9a158b0950a9544cff SHA-256: 286df3457f8c4c999bbc132e9f71226d47d079912a7402f5382f2f164ea368e8

98 Risk Score

Malware Insights

MITRE ATT&CK

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

This PDF sample was flagged as malicious by an ML classifier and contains embedded JavaScript. The JavaScript utilizes `String.fromCharCode` and `eval()` to obfuscate and execute code, a common technique for downloading and running secondary payloads. The presence of `eval()` is a strong indicator of malicious intent, likely to fetch and execute further stages of malware.

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` `9b462e680ed84d2a72481102cf4dfcd77a00e22f9ff29cbb6d310712f60225aa`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	882 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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