PDF malware analysis — malicious · 0491e4e3a96381dc

MALICIOUS

PDF

6.9 KB

MD5: f7b187be434ebba9cb0bac58d6b39bd8 SHA-1: 7d241657a7747d0ab1906eedf789f688d0ff140f SHA-256: 0491e4e3a96381dc11c008a3cc4e3ffc639155b3ce2c9d86abafe1aae488c7ad

328 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains obfuscated JavaScript that leverages the CVE-2009-0658 exploit for JBIG2Decode, a known vulnerability in older Adobe Reader versions. The JavaScript is designed to execute a secondary payload, indicated by the PDF_JS_EXPLOIT_CLUSTER and PDF_UNESCAPE heuristics. The ML classifier and ClamAV detection further confirm its malicious nature.

Machine Learning

Nyx PDF Classifier malicious score 0.9999

Heuristics 9

Adobe Reader JBIG2Decode generic heap-spray exploit critical CVE likely CVE_2009_0658_GENERIC_SPRAY

PDF combines JBIG2Decode image streams with JavaScript heap-spray or decoder scaffolding. This is likely CVE-2009-0658-family Adobe Reader JBIG2 exploitation, but it lacks the stricter Reader-9 version gate or decoded page-word shellcode fingerprint required by the exact rule.
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.
ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION

ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0006_000.js` `1b373d02d61cc5820141ae7e6e88ae3209f8afbb8b01c99279de84a4ab3a5e87`	pdf-javascript-stream	PDF /JS object 6 at offset 0x21A	5505 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).

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