PDF / .TXT malware analysis — malicious · 21a237ed2c5dddaf

MALICIOUS

PDF / .TXT

1.8 KB

MD5: e6d4033fceea2b847977be506e6b3ff2 SHA-1: e31e9201a7a1f5254b821827784147325fa9149b SHA-256: 21a237ed2c5dddafc09e510f0ebb3da84890b7c513db0d49562a979d6bc569d1

136 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1027 Obfuscated Files or Information T1566.001 Spearphishing Attachment

The PDF contains obfuscated JavaScript, indicated by multiple heuristic firings including PDF_EVAL, PDF_UNESCAPE, and PDF_FROMCHARCODE. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript streams, particularly 'legacy_pdfkit_stage_000.js', are likely responsible for downloading and executing a second-stage payload. The presence of these techniques suggests a common attack pattern for delivering malware via malicious documents.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (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_obj111611_000.js` `eb82ebaa33ef5ca9d3a32e3ff628722a2e10dd2b9454d9dd30223991ca165b4c`	pdf-javascript-stream	PDF /JS object 111611 at offset 0x66C	277 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `309a61394424a0bd5b4d9fcc3407896ef9270a9d81868c280c6699df24621faa`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x189	2822 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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