There are several forms of attack that are designed to fraudulently surpass authentication protection.
But the following closely match what the type of attack you're describing.
- Network eavesdropping. This is when an attacker steals id details or credentials from a network by intercepting and reading network traffic that was meant for another user.
Network eavesdropping sounds similar to what you're describing because the attacker would have to listen in or intercept the authentic validation in order to replicate it and reuse it later.
- Cookie replay attacks. Is when the attacker accesses an authenticated session by recycling a cookie stolen from a user with verified session information.
This sounds similar to what you mentioned, but you didn't specify cookies as being the type of authentication. Nevertheless, a possibility.
The following two possibilities are also close to the description of the hack you mentioned.
- Credential theft. This is plain out data theft. Common tricks include phishing or social engineering., and the attacker uses the acquired information to access areas that require authorization.
- Token stealing. In this instance, token is another word for "credentials". The attacker is able to access and replicate the credential data that the user has, and makes use of that to access to privileges and data above his level of clearance.
