PDF malware analysis — malicious · 616764a2d28528a5

MALICIOUS

PDF

22.2 KB Created: 2011-72-51 03:25:00

MD5: c6ce070a83253fe664a92868d96a4e9a SHA-1: 173483feadea2cdf3817608166dcf878f8300e7d SHA-256: 616764a2d28528a5d64aae4b7d453b056ee0ca352548b567a5ba53a0010c02f5

116 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF document contains embedded JavaScript, identified by heuristics like PDF_JAVASCRIPT and PDF_JS_EXPLOIT_CLUSTER. The JavaScript code, although obfuscated, utilizes String.fromCharCode to construct and execute a string, likely a second-stage payload. The ML classifier strongly indicates maliciousness. The primary attack vector is likely spearphishing attachment, leading to client execution via the embedded exploit.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 5

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.
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_obj0001_000.js` `6b40d38062c0c659b36fb6296d666bc9ef0c4f58884cbe285daab6f8aeba341f`	pdf-javascript-stream	PDF /JS object 1 at offset 0x5688	405 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).

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