1. A system for mitigating network attacks, the system comprising: a protected network comprising a plurality of devices; and one or more attack mitigation devices communicatively coupled to the protected network, wherein the one or more attack mitigation devices are configured and operable to employ a recurrent neural network (RNN) to obtain probability information related to a request stream, wherein the request stream comprises a plurality of at least one of: HTTP (hypertext transfer protocol), RTSP (Real Time Streaming Protocol) and/or DNS (Domain Name System protocol) messages; analyze the obtained probability information to detect one or more atypical requests in the request stream and perform, in response to detecting the one or more atypical requests, one or more mitigation actions on the one or more atypical requests in order to block an attack.