PDF malware analysis — malicious · 6c6400044cd0040a

MALICIOUS

PDF

927 B

MD5: 3dc521c18c926dd3d73d46bfcb12f3f4 SHA-1: 8d0b47c38a9706f8b3c3d8b1b328e58f03ee3f6e SHA-256: 6c6400044cd0040a4bd09c2bf0f91c0b0511a4fba24dfd55745030583b306459

156 Risk Score

Malware Insights

MITRE ATT&CK

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

This PDF file contains obfuscated JavaScript that utilizes unescape and String.fromCharCode functions, indicative of exploit code. The script attempts to leverage a PDF object to execute arbitrary code, likely downloading and running a second-stage payload. The ML classifier strongly flags this PDF as malicious, supporting the conclusion of an exploit attempt.

Machine Learning

Nyx PDF Classifier malicious score 0.9998

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.
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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `2f11957571dbd84113e710b4a93706ea49dc585e20026901df5fceb8f81cfa25`	pdf-javascript-stream	PDF /JS object 5 at offset 0x156	553 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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