PDF malware analysis — malicious · 78d437195497f5d8

MALICIOUS

PDF

6.9 KB

MD5: b4f7502371e00f840594388203de526b SHA-1: 750a4cb08ad855145fa90c9a3be270fd9a1e926c SHA-256: 78d437195497f5d854b46364f5ce3ea26b71b4131e84cf9c2b584b462567ee69

388 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

This PDF file contains obfuscated JavaScript that leverages the unescape() function, a known indicator of malicious activity. The JavaScript is designed to exploit the CVE-2009-0658 vulnerability in Adobe Reader, which allows for arbitrary code execution. The primary goal appears to be downloading and executing a secondary payload, as suggested by the exploit cluster and ML classification.

Machine Learning

Nyx PDF Classifier malicious score 0.9987

Heuristics 10

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.
Hex-obfuscated scripting name object critical PDF_OBFUSCATED_NAME_OBJECT

A PDF name object that drives script execution (/JavaScript or /JS) is written with #XX hex escapes to hide it from string-based scanners — e.g. /J#61v#61S#63r#69p#74 decoding to /JavaScript. Legitimate PDF producers always write these names literally; hex-encoding an executable name is a deliberate evasion used by exploit-kit and dropper PDFs.
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` `e1c05c339ecd12a9ed1c1c71a86bf29592c14b04f5f1209a01290d4f5250572f`	pdf-javascript-stream	PDF /JS object 6 at offset 0x219	5492 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s).

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