Editing Transmission Control Protocol (section)

===TCP veto===
An attacker who can eavesdrop and predict the size of the next packet to be sent can cause the receiver to accept a malicious payload without disrupting the existing connection. The attacker injects a malicious packet with the sequence number and a payload size of the next expected packet. When the legitimate packet is ultimately received, it is found to have the same sequence number and length as a packet already received and is silently dropped as a normal duplicate packet—the legitimate packet is ''vetoed'' by the malicious packet. Unlike in connection hijacking, the connection is never desynchronized and communication continues as normal after the malicious payload is accepted. TCP veto gives the attacker less control over the communication but makes the attack particularly resistant to detection. The only evidence to the receiver that something is amiss is a single duplicate packet, a normal occurrence in an IP network. The sender of the vetoed packet never sees any evidence of an attack.<ref>{{cite conference |author1=John T. Hagen |author2=Barry E. Mullins |title=2013 IEEE PES Innovative Smart Grid Technologies Conference (ISGT) |chapter=TCP veto: A novel network attack and its Application to SCADA protocols |journal=Innovative Smart Grid Technologies (ISGT), 2013 IEEE PES |pages=1–6 |year=2013|doi=10.1109/ISGT.2013.6497785 |isbn=978-1-4673-4896-6 |s2cid=25353177 }}</ref>