Short block sizes make the webserver vulnerable to hit the same hash for multiple inputs. By observing the data for a longer period of time, an attacker can recover secure HTTP cookies.
Security Assessment
CVSS Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Vulnerability Information
Short block sizes make the webserver vulnerable to hit the same hash for multiple inputs. By observing the data for a longer period of time, an attacker can recover secure HTTP cookies.
Guides
To prevent SWEET32, make sure that you only use cypher suites with large block sizes. Refer to Secure TLS Configuration for more information on how to configure good cypher suites.