PDF malware analysis — malicious · 138d706e8c58f432

MALICIOUS

PDF

2.6 KB

MD5: 23699aad7f184f96bf4709b371599ae3 SHA-1: 5487daabee72ae4d423490396a268c8629c77222 SHA-256: 138d706e8c58f432fc10f0851fc0cb24c3f53354f97eada19762c8e5d119ef04

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, which is heavily obfuscated and uses eval() and String.fromCharCode() functions. This script is designed to decode and execute a second-stage payload, likely from a remote source. The ML classifier strongly indicates maliciousness, and the presence of exploit cluster heuristics further supports this. The primary function of the script appears to be downloading and executing a secondary payload.

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` `7c616807e1a9ee360ce4b8b1c326f983419f93e0117b923ea9b093e7fb45d320`	pdf-javascript-stream	PDF /JS object 111711 at offset 0x197	2569 bytes
`javascript_obj111712_001.js` `39fd3be096eb3ae3a608b70b20e3d93df12c587e64dfe6fe52e31802e291d659`	pdf-javascript-stream	PDF /JS object 111712 at offset 0x850	551 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).

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