PDF malware analysis — malicious · 7d838b78b55a868b

MALICIOUS

PDF

16.2 KB Created: 2010-03-07 09:18:43 Authoring application: cK6C0ObYdN (via aMYMfs)

MD5: 3f00c8ddeada5eb5ad32dd41ba132a0a SHA-1: a85db9fd90264294485e7f34f7546fd225e45507 SHA-256: 7d838b78b55a868b0eede203f37e6cb0c1745ee6c3b407482f9353dac6d55139

156 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF file contains embedded JavaScript that utilizes `eval()` and `fromCharCode()`, indicating an attempt to obfuscate malicious code. The ML classifier strongly flags this PDF as malicious, and the heuristics point to a known JavaScript exploit cluster. The embedded JavaScript is likely responsible for downloading and executing a secondary payload, which is a common technique for initial compromise.

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.
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` `92f9871c582b81bdcc19bbc237ee4cd71f683fd0781c04c968aa70bd069bd265`	pdf-javascript-stream	PDF /JS object 7 at offset 0x23F	15393 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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