PDF malware analysis — malicious · 66f7588bc1e5076d

MALICIOUS

PDF

177.8 KB

MD5: cdc675c4a27b2b03cab81f69da1f20ac SHA-1: 1a22bfd774f853737be53b3c9db4a381c68f6a55 SHA-256: 66f7588bc1e5076d30ceb9c6687285cd4ad263ceadaeab2bed560581fdd75f33

136 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, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT' and 'PDF_JS_EXPLOIT_CLUSTER'. The JavaScript code, although obfuscated, appears to be a base64 decoder and is likely responsible for executing a malicious payload. The ML classifier strongly flags this PDF as malicious, supporting the conclusion that it's designed for exploitation.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

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.
ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX

Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0008_000.js` `d1986d0a1a4071fd5fb36520b7f45fca7916fae33fe41070bda808bd9d312916`	pdf-javascript-stream	PDF /JS object 8 at offset 0x1E7	60421 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).

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