PDF malware analysis — malicious · 03897c058773dfc3

MALICIOUS

PDF

11.4 KB Created: 2010-08-25 21:43:44 +04:00 Authoring application: kHxqQB_ (via a1dc51ee5)

MD5: dd0810d6bd8e945947a1e128a0c3c7fb SHA-1: 4c708b218ae8280c8817c13ec1cd03a2f60fa858 SHA-256: 03897c058773dfc309fcaff37df812b74d5186efbf3e755310416a5b1e77e619

164 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF file contains embedded JavaScript that is heavily obfuscated. Heuristics indicate the use of eval() and String.fromCharCode, common techniques for JavaScript exploit delivery. The ML classifier strongly flags this PDF as malicious. The JavaScript likely attempts to download and execute a second-stage payload, as suggested by the exploit cluster firing.

Machine Learning

Nyx PDF Classifier malicious score 0.9998

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)
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)
Optional Content Group with action trigger low PDF_OPTIONAL_CONTENT

Optional Content Group (layer) co-occurs with an action trigger — content can be selectively hidden from viewers or scanners while the action still fires on open
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_obj0011_000.js` `7605bc3d5ec96142d111f2590206986d422f84f2a78037b99721515605a8afe5`	pdf-javascript-stream	PDF /JS object 11 at offset 0x2416	1108 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`javascript_obj0013_001.js` `62bb563050c9faacaee14ad16dfa48b8fc9c37f4512d3642d1497af63f473dbd`	pdf-javascript-stream	PDF /JS object 13 at offset 0x26A1	507 bytes
`javascript_obj0015_002.js` `3e79ba82b47a540e2e69dbdaa89db78200bc70f8bda872a28d6632383d42afac`	pdf-javascript-stream	PDF /JS object 15 at offset 0x283A	136 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).

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