Nemucod PDF malware analysis — malicious · 9d5783dc978bcaf5

MALICIOUS

PDF

30.6 KB Authoring application: PyPDF2

MD5: aa366faf39815b01616682737728c190 SHA-1: ec5efbe766da50c16c89aff90fe328cda68411cc SHA-256: 9d5783dc978bcaf5e9f30df628bc4a41c2d32811221f58859e051a8cf171aef2

226 Risk Score

Malware Insights

Nemucod · confidence 95%

MITRE ATT&CK

T1059.001 PowerShell

The PDF file contains embedded JavaScript, flagged by multiple heuristics including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The ML classifier and ClamAV detection strongly indicate maliciousness, identifying the family as Nemucod. The extracted JavaScript artifacts, though obfuscated, are typical of Nemucod's behavior, which involves downloading and executing a second-stage payload. The ClamAV detection name 'Txt.Downloader.Nemucod-6769573-0' is included as a primary IOC.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

ClamAV: Txt.Downloader.Nemucod-6769573-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Txt.Downloader.Nemucod-6769573-0
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution
Suspicious extracted artifact medium 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.
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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0004_000.js` `e012d6497634a6827da4e76e9db6a457dc9181731490d95f2109002e843d7bd1`	pdf-javascript-stream	PDF /JS object 4 at offset 0xD7	17425 bytes
Detection ClamAV: Txt.Downloader.Nemucod-6769573-0 Obfuscation or payload: likely Carved artifact contains 48 eval/decoder/string-building token(s). Carved artifact contains 2 long hex-escaped blob(s).
`javascript_obj0004_001.js` `21599adee8d7aa1fb5b5f0da6632173704e21ab545aee6027ca6f962302465bc`	pdf-javascript-stream	PDF /JS object 4 at offset 0xD7	737 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long hex-escaped blob(s).

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