The AWS Public RDS Restore rule detects the creation of a new Amazon RDS database instance from a snapshot that is publicly accessible. This rule is important for identifying potential data exfiltration activities since restoring a database instance publicly could expose sensitive data to unauthorized users. The rule checks CloudTrail logs for the event 'RestoreDBInstanceFromDBSnapshot' or 'CreateDBInstance', reviewing if the newly created instance is accessible publicly. The rule is triggered if a restore is completed and the instance is marked as 'publiclyAccessible'. A risk associated with this action involves inadvertently exposing data that should remain private, especially if it is deemed sensitive or critical. Given the potential for misuse, this rule is categorized with high severity. Regular monitoring is crucial, especially in environments where sensitive customer information is stored in RDS instances.