A method and system for detecting impersonated network traffic by a protected computing device and a network protection system. The method includes the computing device receiving installation of a browser application, the browser application configured to generate requests to communicate with other computers via the World Wide Web and receiving a configuration for the browser application. The browser application is configured to obtain a short-lived password (SLP) in coordination with generating a request and insert the short-lived password into the generated request before transmitting the request. The SLP is synchronized with an expected value generated by the network protection system. The transmitted request is passed to the network protection system and treated as legitimate network traffic by the network protection system only if the network protection system detects and verifies the SLP.