Ever Heard of Replay Attack?

Replay attack also called a repeat attack or playback attack is a cyber-crime in which data is maliciously duplicated and transferred to the recipient. The sender or a third-party fraudulently disrupt the network with the purpose of replicating the data before it gets to the receiver. 

Another way of describing such an attack is: “an attack on a security protocol using a replay of messages from a different context into the intended (or original and expected) context, thereby fooling the honest participant(s) into thinking they have successfully completed the protocol run.

The false replica looks exactly the same as the original, was interpreted verbatim and might not be decrypted, making it difficult for the network’s security protocol to see that it is an attack. 

An explainer context

Hassan and Nella are the two parties involved in a peer-peer transaction. Hassan sends messages and Password to Nella as required for the transaction to be successful, Nella receives the details sent, Khalid, an unauthorised user penetrates into the network and eavesdropped on every detail sent, he creates an exact replica of the data and sends it to Hassan for approval, Hassan grants access with the thought that the hash was from Nella.