Stylish - Custom themes for any websiteSecurity Analysis

Extension intercepts network traffic and sends data externally — potential man-in-the-middle behavior.

Extension has access to all sites and captures keyboard input — behavior consistent with a keylogger.

Dynamically sets a script's src attribute to load external code at runtime.

Creates functions from strings, similar to eval(), often used to hide malicious code.

Listens for keyboard events, a common technique used by keyloggers.

Injects and executes scripts in web pages programmatically.

Dynamically creates script elements, potentially loading external malicious code.

Uses eval() to execute dynamic code, a common technique for obfuscation and code injection.

Assigns an external URL to .src property: https://i.imgur.com/UhKm0IQ.png

Creates a function from a string (new Function()), similar to eval().

JavaScript files are accessible to ALL websites. Any page can load and interact with these scripts, enabling web→extension attacks.

Content script runs at document_start in ALL frames on ALL URLs. This gives the extension deep access to every page load, including iframes.

Extension tracks open tabs and communicates with external servers — potential browsing surveillance.

Decodes base64 data, commonly used to hide malicious payloads.

Uses XMLHttpRequest to make network calls.

Makes HTTP requests to external servers, may be used for data exfiltration.

Sends messages via Chrome runtime, could communicate with external services.

Dynamically creates iframe elements, which can be used to load external content or hide malicious UI.

Modifies window.location to redirect the user, potentially to phishing or malicious pages.

JavaScript file could not be parsed. May contain obfuscated or minified code.

Fetches external URL: https://userstylesapi.com/content/config

Line exceeds 5000 characters (entropy: 5.360490672577832)

This extension does not define a Content Security Policy. A CSP helps prevent XSS and code injection attacks.

Web-accessible resources use <all_urls> or wildcard patterns, exposing resources to every website.

Sets innerHTML directly, which can lead to XSS if used with untrusted data.

Reads or writes to localStorage, which may contain sensitive site data.

Encodes data to base64, may be used for data exfiltration.

Creates a Web Worker, which runs code in a separate thread — can be used for background computation or crypto mining.

String with entropy 5.95 bits — may be encoded/encrypted data

Extension accepts messages from 2 external pattern(s). Verify these are trusted origins.

static/js/main.js

static/js/service-worker.js