PDF malware analysis — malicious · 1fbc00f8cf21f48c

MALICIOUS

PDF

4.0 KB

MD5: e3456eed0394348eea15836d7a63ec9f SHA-1: a99b683c3c919e4a06730a655fb8ca24be9d14a5 SHA-256: 1fbc00f8cf21f48cbd9870073b11108783c1fb66fdfb67a8a5c42850897f929b

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

This PDF file contains embedded JavaScript, flagged by multiple heuristics including PDF_JAVASCRIPT and PDF_JS. The ML classifier strongly indicates maliciousness. The deobfuscated JavaScript stream (acroform_b64_00.js) likely contains code to download and execute a second-stage payload, though the exact mechanism is obscured. The presence of eval() and String.fromCharCode calls further suggests dynamic code execution.

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` `40a6ed57c2a0561cccfd48087bf7babe17b32da41cdb3fc3cbf9199378d53cd0`	pdf-javascript-stream	PDF /JS object 13 at offset 0x368	6225 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` `46d276f54672986dfc0d80a2fe870491beb17fcf217f6642c77cb81dc38b6a6e`	deobfuscated-js	PDF AcroForm base64 (decompressed) at offset 0x99D	3515 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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