The KRBTGT account is a critical account used by the Kerberos authentication protocol. The fact that the hash for KRBTGT.CORP.LOCAL was successfully collected during the attack indicates that the attacker may have gained access to Kerberos tickets and could potentially impersonate users. Rotating the KRBTGT password helps mitigate the risk of Kerberos ticket forging, which is a common post-exploitation technique in attacks such as Pass-the-Ticket and Golden Ticket attacks. This will prevent attackers from using stolen hashes to impersonate users or gain unauthorized access to the domain.