ExpressVPN: VPN & proxy browser extensionSecurity Analysis

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

Extension communicates with native apps and executes dynamic code — potential sandbox escape vector.

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

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

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

Dynamically creates script elements, potentially loading external malicious code.

Accesses browser cookies programmatically, could be used to steal session tokens.

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

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

externally_connectable uses broad patterns, allowing any website to establish a messaging channel with the extension. This can be exploited to trigger extension actions from malicious pages.

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 has cookie access and sends data to external servers — potential session token theft.

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

Uses XMLHttpRequest to make network calls.

Decodes base64 data, commonly used to hide malicious payloads.

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

JavaScript file could not be parsed and has high entropy. May contain obfuscated code.

Line exceeds 5000 characters (entropy: 5.241493636960235)

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

Extension uses tab tracking APIs (onUpdated/query) and communicates with external servers — potential browsing surveillance.

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

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

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

object-src is not set to 'none'. Plugins like Flash can be embedded, which may allow code execution.