Se dice cuando el atacante accede a la información, pero la deja como estaba sin alterar su contenido.

An attack against an authentication protocol where the Attacker intercepts data traveling along the network between the Claimant and Verifier, but does not alter the data (i.e., eavesdropping). [NIST SP-800-63:2013]

An attack that does not alter systems or data. [CNSSI_4009:2010]