PDF malware analysis — malicious · 66313df8e88596c9

MALICIOUS

PDF

302.7 KB Created: 2009-05-14 12:40:13 +08:00 Authoring application: PScript5.dll Version 5.2.2 (via Acrobat Distiller 7.0 (Windows))

MD5: 88f4bea6a9f22578315e26f086fc2fb1 SHA-1: 38d45f53a134fb7e26398a2cd63b24e4706c9fc0 SHA-256: 66313df8e88596c90f43f55cb274aa952590408f3c4a29fae39f31e68452ae73

270 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that utilizes the unescape function, a known technique for obfuscating exploit code. Heuristics indicate this is part of a cluster of PDF JavaScript exploits, specifically targeting CVE-2009-0658, an Adobe Reader JBIG2Decode heap-spray vulnerability. The script's primary function appears to be preparing for and executing a heap spray, which is a common precursor to downloading and running additional malicious content.

Machine Learning

Nyx PDF Classifier malicious score 0.9998

Heuristics 9

Adobe Reader JBIG2Decode heap-spray exploit critical CVE likely CVE_2009_0658

PDF combines JBIG2Decode image streams with a Reader 9 JavaScript heap-spray stage. This is the in-the-wild Adobe Reader/Acrobat JBIG2Decode exploit shape associated with CVE-2009-0658.
JBIG2 + active content high CVE related PDF_JBIG2_ACTIVE_CONTENT

JBIG2Decode appears with JavaScript/XFA/RichMedia — a related indicator for JBIG2 parser-exploit families including CVE-2021-30860 and CVE-2009-0658, but not a unique CVE fingerprint.
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)
JBIG2Decode filter medium PDF_JBIG2

JBIG2 image decoder present — historically used in zero-click exploits
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.
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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
- http://ns.adobe.com/pdf/1.3/
- http://ns.adobe.com/xap/1.0/
- http://purl.org/dc/elements/1.1/
- http://ns.adobe.com/xap/1.0/mm/

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0021_000.js` `c108b22775026c92a327460eadf0bbd611e7bcedb0dd8e6af00e3568acd404bf`	pdf-javascript-stream	PDF /JS object 21 at offset 0x37E	540 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`jbig2_00_off0000065a.bin` `0d68c3d2a2889a32d223a48c19770739da541e6143fc26c917b76529c28da006`	pdf-jbig2-stream	PDF JBIG2 stream at offset 0x65A	3739 bytes

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