PDF malware analysis — malicious · ea838fed0c882cea

MALICIOUS

PDF

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

MD5: 2988d89d4ed9654599f903be50630072 SHA-1: f48ffaa1c3bcff391b91300df1b41cbf94778238 SHA-256: ea838fed0c882cea8a6dafd4850af2a98d992142dcedf1703b0bdb8255cc7234

98 Risk Score

Malware Insights

MITRE ATT&CK

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

This PDF sample 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 as malicious. The primary attack pattern involves leveraging JavaScript to execute arbitrary code, likely to download and run a second-stage payload. The specific JavaScript code was too obfuscated to determine its exact function, but the presence of eval() is a strong indicator of malicious intent.

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` `2bc50cd0cb5676b940d587f0c7fee0bf239f0f72b746ab0aee38d1ff93bc1a52`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	529 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 6 eval/decoder/string-building token(s).

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