PDF malware analysis — malicious · 6fb50f1c1030623a

MALICIOUS

PDF

6.1 KB

MD5: a777bda7cae1ecc9b2e20255c308681f SHA-1: 38c46f8ac64574cddc7b846014d50d49c799c486 SHA-256: 6fb50f1c1030623a91482569fde6350cdf643774b64a473f097219de5a3aa2ef

368 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF file contains heavily obfuscated JavaScript, indicated by multiple critical heuristic firings including PDF_OBFUSCATED_NAME_OBJECT and PDF_JS_EXPLOIT_CLUSTER. The JavaScript utilizes unescape() and exploits CVE-2008-2992 via util.printf, suggesting it's designed to download and execute a secondary payload. The ML classifier and ClamAV also flagged this as malicious.

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` `811a9f574cf0c8f59104239c09136e5c8455e9156758d2d02a19c2054c835f3a`	pdf-javascript-stream	PDF /JS object 6 at offset 0x1A1	5155 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` `51d8ad463fa6281c4ac99a0bc98e36f832564a00d9ee574100b9d65bc463782d`	deobfuscated-js	generic stage recovery percent-decode from JavaScript object 6 at offset 0x1A1	5153 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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