PDF malware analysis — malicious · 03f9944ae0f1e6ac

MALICIOUS

PDF

2.7 KB

MD5: 31efe79b8192887ec9e30cd70b89f031 SHA-1: f1f49e4f343fb3db3505c8d0b3a117c947a7abc5 SHA-256: 03f9944ae0f1e6acdee6c6b0c3616fbf7ea1e1be037dba053d303e2cefb9877d

156 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF contains embedded JavaScript that utilizes eval() and String.fromCharCode() functions, indicating an attempt to obfuscate malicious code. This JavaScript is designed to download and execute a second-stage payload, as evidenced by the critical PDF_JS_EXPLOIT_CLUSTER heuristic and the ML classifier's high confidence score. The embedded JavaScript files, javascript_obj111711_000.js and javascript_obj111712_001.js, are the primary indicators of this malicious activity.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

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)
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj111711_000.js` `1cea06f5279435ae7329212687744a86a3a68b3911e43f67f00476d950b67053`	pdf-javascript-stream	PDF /JS object 111711 at offset 0x197	371 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`javascript_obj111712_001.js` `833dfdc37c71b7d50d35154c5e3c424048ab9ffb65378070eaa9a2b3d8c77d9d`	pdf-javascript-stream	PDF /JS object 111712 at offset 0x247	2912 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).

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