PDF malware analysis — malicious · 8103c0ded29ee032

MALICIOUS

PDF

5.8 KB

MD5: 985bb56cc292cdf7691d668f008a39a0 SHA-1: 37d1c781288720c3837cf8eaa32ced6223e3a588 SHA-256: 8103c0ded29ee03269f0cd2846e1fc688a391b0fb7a96660e4ec645f48ac1055

368 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF file contains heavily obfuscated JavaScript, indicated by multiple heuristic firings including PDF_OBFUSCATED_NAME_OBJECT and PDF_JS_EXPLOIT_CLUSTER. The JavaScript utilizes `unescape` and is associated with the CVE-2008-2992 exploit, suggesting it's designed to download and execute a second-stage payload. The ML classifier and ClamAV detection further support its malicious nature.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 9

util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992

PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (matched in decompressed stream)
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)
Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY

Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0006_000.js` `b95c80ce8e85c160ff1d805a42c063155b564b4ac608e72039416838478b9efa`	pdf-javascript-stream	PDF /JS object 6 at offset 0x193	5009 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`generic_stage_recovery_000.js` `91f7946a998268430fa17a6eed0ceb57ae89c548afc5a797dee084c9126805ea`	deobfuscated-js	generic stage recovery percent-decode from JavaScript object 6 at offset 0x193	5007 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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