What is Replay Attack?

A replay attack is a class of network attack in which an aggressor detects a data communication and deceitfully has it deferred or repeated. The postponement or repeat of the data transmission is carried out by the sender or by the malevolent entity, who intercepts the data and retransmits it. In other words, a replay attack is an attack on the safety protocol using replays of data transmission from another sender into the proposed into reception system, thereby fooling the members into believing they have effectively completed the data transmission. Replay attacks help attackers to gain access to a grid, gain data which would not have been effortlessly available or complete a replica transaction.

Note: A replay attack is also known as a playback attack.

Averting a Replay Attack

Averting such an attack is all about having the right technique of encryption. Encrypted communications carry "keys" within them, and when they're deciphered at the end of the transmission, they open the communication. In a replay attack, it doesn't matter if the aggressor who intercepted the original communication can read or decrypt the key. All he or she has to do is seize and resend the entire thing — communication and key — together.

To counter this possibility, both sender and receiver should establish a completely random session key, which is a type of code that is only valid for one transaction and can't be used again. Another pre-emptive measure for this type of attack is using time-stamps on all messages. This averts hackers from resending messages sent longer ago than a certain length of time, thus reducing the window of chance for an attacker to eavesdrop, siphon off the message, and resend it.

Another technique to avoid becoming a victim is to have a password for each transaction that's only used once and superfluous. That guarantees that even if the message is verified and resent by an attacker, the encryption code has perished and no longer works.