PDF malware analysis — malicious · 16cedbb7fe1ee6d9

MALICIOUS

PDF

15.3 KB Created: 2009-09-19 19:48:26 Authoring application: PDF Library 10.6.7 (via PDF Library 1.6.6)

MD5: a24b385d2a8b055919f678b22920d80d SHA-1: 8ab9bc7c1e5577b49c96019652746bb6c701a6ec SHA-256: 16cedbb7fe1ee6d9092602ebdb7063935f7722536c337f640ce93cb81e3fbd4a

176 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode() functions, indicative of exploit code. The ML classifier strongly flags this PDF as malicious. The JavaScript is heavily obfuscated but its presence and the exploit cluster heuristics suggest it is designed to download and execute a secondary payload, likely exploiting a client vulnerability.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 7

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.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX

Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0007_000.js` `a43b22bf9dec9a4a68e1e97e2519bef75b6db19ae4f8dc5a0b635630cdc096ec`	pdf-javascript-stream	PDF /JS object 7 at offset 0x268	163026 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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