PDF malware analysis — malicious · 64cb40db52abab6a

MALICIOUS

PDF

12.1 KB Created: 2009-05-09 13:44:39 Authoring application: daKX2W29vefrFi (via JB5zKY90NY7k)

MD5: d1ae4eb477958cebd027ab7db9f791d3 SHA-1: a8aa4bfdbee4668f94ceaf7fef8399f3dac6bab8 SHA-256: 64cb40db52abab6ac00b00390924031c13fd96f6d28561a6505cb86cb4163624

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 using string concatenation and `fromCharCode`. This script is designed to decode and execute a malicious payload, likely by exploiting a known PDF vulnerability. The ML classifier strongly indicates malicious intent, and the presence of JavaScript points to a common delivery method for malware.

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.
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (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` `1e7ab719a282b757f774f701228b9547b5b1cd97cdee60d7ce3fec8919f5c4e6`	pdf-javascript-stream	PDF /JS object 7 at offset 0x239	11140 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).

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