PDF malware analysis — malicious · b3160a872a720c60

MALICIOUS

PDF

4.0 KB

MD5: d6e97abf067870894b593d67d2f9c073 SHA-1: 1585be6a0733db5bfa6a4bde41cb5cb2892ed38e SHA-256: b3160a872a720c607ddb6bd43d4f44da1c953e751fe2f39cbeb217ed838da5ed

156 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.001 Malicious Link

The PDF file contains embedded JavaScript that utilizes the `eval()` function and `String.fromCharCode()` to deobfuscate and execute malicious code. The critical heuristic firing for CVE-2008-2992 indicates the use of `util.printf` to exploit a vulnerability in Adobe Reader, likely to download and execute a second-stage payload. The ML classifier strongly supports the malicious nature of this PDF.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

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. (identified after JavaScript deobfuscation)
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
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.
String.fromCharCode low PDF_FROMCHARCODE

String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0013_001.js` `44b4ac0f5012fd3cea3abdc9d26842c81d91bf9083dfc4f06def88bfe0f5028f`	pdf-javascript-stream	PDF /JS object 13 at offset 0x368	6353 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`acroform_b64_00.js` `e31b00d6927b582ba6b81b292044af52732a2bd5b22f3393aca1685f89c44e28`	deobfuscated-js	PDF AcroForm base64 (decompressed) at offset 0x99D	3611 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`custom_b64_stage_000.js` `85fe71200c33f398824631ccde606ec4fbbce8035fb8611c145accabab2137e1`	deobfuscated-js	custom Base64 decoded JavaScript layer 2 (PDF /JS object 13) at offset 0x95E	2025 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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