PDF malware analysis — malicious · 66b479de97da4556

MALICIOUS

PDF

14.5 KB

MD5: 4dbbfef601e92dc198230b75bc3e310f SHA-1: 19380fb2fcf30caf151210bb2179495cbf219860 SHA-256: 66b479de97da4556fc2896bc5001539293febc1b62912ab0598fbbbb5fb07763

216 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that uses String.fromCharCode and eval() to execute obfuscated code. This script is designed to decode and run a second-stage payload, as indicated by the PDF JavaScript exploit cluster heuristics and ClamAV detection. The primary function of the script is to download and execute a further malicious component, likely delivered via spearphishing.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 7

PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER

PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
ClamAV: Pdf.Exploit.Dropped-94 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Dropped-94
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_obj0076_000.js` `c28effae366bd4b2a63fe29aea090a07947ae4e73aa9efc1cf87e16e006e7288`	pdf-javascript-stream	PDF /JS object 76 at offset 0x38C0	144 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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