The Intrusion Detection System plays a vital role in the security factor of a network. An evasion technique modifies the attacks for evading the network so that the intrusion detection system (IDS) does not recognize it. An Advanced Evasion Techniques(AET) are techniques which evolves new attacks by combining several existing attacks thereby it evades the intrusion detection system. An AET method provides a way for an attacker to obfuscate malicious data and make him penetrate the network defences unnoticed. By combining attacks, the advanced evasions by passes most security solutions making the traffic to look normal. This paper gives a review about the advanced evasion techniques that the attacker uses for evasion. © 2016, International Journal of Pharmacy and Technology. All rights reserved.