PDF malware analysis — malicious · a444525d16b729bd

MALICIOUS

PDF

22.1 KB

MD5: ebb095d7f27a38d8106d8a7a1fd018cd SHA-1: 923a758653113282cd801adf0fa29562655f9408 SHA-256: a444525d16b729bdc8b03f0936a5bd9f00e804843081edbc961add51d9b0dd47

124 Risk Score

Malware Insights

MITRE ATT&CK

T1204.002 Malicious File

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT and PDF_JS. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript, found in javascript_obj3332_000.js, is likely responsible for exploiting a vulnerability within the PDF reader to download and execute a secondary payload. The presence of unescape() and String.fromCharCode functions suggests obfuscation within the script.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 7

unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
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)
ASCII85Decode filter (with exploit indicators) low PDF_FILTER_85

ASCII85 encoding filter present alongside exploit delivery indicators — uncommon outside of obfuscation
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_obj3332_000.js` `e8eee5675870cdc9765bce0fef43b5ae82038b2ba235ad3631dec5515faee4b5`	pdf-javascript-stream	PDF /JS object 3332 at offset 0x561B	288 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).

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