PDF malware analysis — malicious · 638a81d82d6269fc

MALICIOUS

PDF

69.0 KB Created: 2010-03-15 07:18:34 Authoring application: bIXYbKxQxY9C8 (via maGKAyltOMBt)

MD5: 3512ae3831bfc7076429177025f77f4c SHA-1: e21dd3cede55ddb3bb6553ee49c5eb38d6f1bd83 SHA-256: 638a81d82d6269fc3db1744bb4f2ffa0d56c1c179ee30631544514cfb0b6c883

156 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF file contains embedded JavaScript that utilizes `eval()` and `String.fromCharCode()`, indicating an attempt to obfuscate malicious code. The critical heuristic 'PDF_JS_EXPLOIT_CLUSTER' strongly suggests this JavaScript is designed to exploit a vulnerability. The ML classifier also flagged the PDF as malicious with high confidence. The primary IOC is the embedded JavaScript file itself, which likely contains the malicious payload.

Machine Learning

Nyx PDF Classifier malicious score 0.9999

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.
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` `68f6b6085a8cf2a159ac13774f40c4271adfeeef901a419eb3351e4b53b8e19c`	pdf-javascript-stream	PDF /JS object 7 at offset 0x233	69484 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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