NIDS evasion

Summary
This plugin configures OVS for NIDS evasion (see the 'Prefs' panel). NIDS evasion options are useful if you want to determine the quality of the expensive NIDS you just bought. TCP Evasion techniques : - Split : send data one byte at a time. This confuses NIDSes which do not perform stream reassembly - Injection : same as split, but malformed TCP packets containing bogus data are sent between normal packets. Here, a 'malformed' tcp packet means a legitimate TCP packet with a bogus checksum. This confuses NIDSes which perform stream reassembly but do not accurately verify the checksum of the packets or which do not determine if the remote host actually receives the packets seen - Short TTL : same as split, but a valid TCP packets containing bogus data are sent between normal packets. These packets have a short (N-1), meaning that if the NIDS is on a gateway, it will see these packets go through, but they will not reach the target host. This confuses NIDSes which perform stream reassembly but do not accurately check if the packet can actually reach the remote host or which do not determine if the remote host actually receives the packets seen - Fake RST : each time a connection is established, OVS will send a RST packet with a bogus tcp checksum or a bogus ttl (depending on the options you chose above), thus making the IDS believe the connection was closed abruptly. This confuses badly written NIDSes which believe anything they see. Warning: those features are experimental and some options may result in false negatives! This plugin does not do any security check.