In some implementations, a device may detect loading of a first web page associated with a domain, and may create an inline frame element that references a second web page associated with the domain. The second web page may require an authenticated user session to access particular content of the second web page. The device may insert the inline frame element into code for the first web page, and may transmit a request for the second web page based on inserting the inline frame element into the code for the first web page. The device may receive a response to the request for the second web page, and may determine whether there is an authenticated user session for the domain based on the response. The device may selectively perform an action based on determining whether there is an authenticated user session for the domain.