PDF / .TXT malware analysis — malicious · b718d8cb785eeecf

MALICIOUS

PDF / .TXT

4.0 KB

MD5: efa79d51dba59247af2690f158b9bb4f SHA-1: 8efdd8ba3e8fd001f77f8ded8b108bc26db04d60 SHA-256: b718d8cb785eeecf7b48b39e7561c0d1b5ad9e979bd0b03dd48f2b42c2c9f46c

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.007 JavaScript

The PDF contains embedded JavaScript, flagged by multiple heuristics including PDF_JAVASCRIPT and PDF_JS. The JavaScript stream, specifically the 'acroform_b64_00.js' artifact, utilizes eval() and String.fromCharCode, indicating obfuscation. The ML classifier strongly flags this PDF as malicious. The primary intent appears to be downloading and executing a second-stage payload, as suggested by the obfuscated script and the presence of extracted JavaScript files.

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. (matched inside decoded stream)
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0013_001.js` `1e0811faad4206341deb629c92d69ecf9d5628de506132faee6766b06698b7fe`	pdf-javascript-stream	PDF /JS object 13 at offset 0x368	6281 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`acroform_b64_00.js` `10ad908b95832e1837c5a964d4ac7af4d5cce37dc9488b5a9307e490e7ceb5cc`	deobfuscated-js	PDF AcroForm base64 (decompressed) at offset 0x99D	3557 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 5 long base64-like blob(s).

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