1. A system, comprising: one or more server computers communicatively coupled to a network, said one or more server computers running: A) a database configured to store, for each of one or more web applications hosted on said one or more server computers, a signature comprising a regular expression pattern identifying a session state, said session state indicating a status of a user of said one of said one or more web applications; B) one or more proxy servers configured to: i) receive, from a client computer communicatively coupled to said network, a request for an action performed by said one or more server computers via one of said one or more web applications; ii) determine whether said request includes a browser cookie; iii) responsive to a determination that said request includes said browser cookie, determine whether said browser cookie matches said regular expression pattern for said one of said one or more web applications; and iv) responsive to a determination that said browser cookie matches said regular expression pattern, perform said action by said one or more server computers.