Replay attack


Replay attack (also known as playback exploit) is a form of network exploit in which a valid data transmission is maliciously or fraudulently repeated or delayed.

Replay attack is carried out either by the originator or by an Attacker who intercepts the data and re-transmits it, possibly as part of a masquerade attack by IP packet substitution.

Use case#

Suppose Alice wants to prove her identity to Bob. Bob requests her password as proof of identity, which Alice dutifully provides (possibly after some transformation like a hash function); meanwhile, Eve is eavesdropping on the conversation and keeps the password (or the hash). After the interchange is over, Eve (posing as Alice) connects to Bob; when asked for a proof of identity, Eve sends Alice's password (or hash) read from the last session, which Bob accepts thus granting access to Eve.

More Information#

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