PDF malware analysis — malicious · 128a55de645bf538

MALICIOUS

PDF

2.8 KB

MD5: 468a7f315218b9698678d00351d154e2 SHA-1: acfbf69b5ea57734eb832c5fd41a95712501b67d SHA-256: 128a55de645bf53804b3aba2f7db554876e25571d06d24482ba7191bee2d7b0c

156 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript streams that utilize eval() and String.fromCharCode() functions, indicating obfuscated code execution. The primary script, javascript_obj111612_001.js, is heavily obfuscated but appears to be constructing a URL or command for a second-stage download. The ML classifier strongly flags this PDF as malicious, supporting the conclusion that it's designed to deliver a 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_obj111611_000.js` `d824a5ecc80892510b44c03da11aa2bbe332880f27f19f9799a101238d5443db`	pdf-javascript-stream	PDF /JS object 111611 at offset 0x197	258 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`javascript_obj111612_001.js` `68f2842022d62d9b9ef0c06c74c111df159b9fa91f328661338ceb411c0ca0d4`	pdf-javascript-stream	PDF /JS object 111612 at offset 0x268	3361 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).

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