PDF malware analysis — malicious · f5ac158c038ffed3

MALICIOUS

PDF

22.4 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode

MD5: af1355cd245d5fee255f9778a0457758 SHA-1: b12c914173e3accd105089a93d345c204359d7b1 SHA-256: f5ac158c038ffed345c77f1879b0a130b9cfa7aebe101cab32d2bd803598f67b

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell T1059.007 Command and Scripting Interpreter: JavaScript/TypeScript

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream utilizes `String.fromCharCode` and an `eval()` call, suggesting obfuscation and dynamic code execution. The ML classifier strongly flags this PDF as malicious. The primary intent appears to be the execution of the embedded JavaScript, which likely downloads and executes a second-stage payload.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 5

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_obj0001_000.js` `ce5705511d4028a6313bfec6e46f953b74f44d2c16d8b53cd8f11fcbb6413790`	pdf-javascript-stream	PDF /JS object 1 at offset 0xA	509 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

Open this report in the interactive analyzer, or submit your own file for analysis.