Sometimes also called a replay attack, a “Playback Attack” is a form of cyber assault on a network in which packets of valid data is intercepted and then maliciously duplicated and/or delayed.
A prominent reason why somebody would execute this form of attack is to obtain access to accounts; in an overly simplified example, if somebody sends in their password to a site & there is a malicious actor doing such an attack on the site, then the malicious actor would now have a copy of the password and be signed into the account.