The rule named 'AWS Security Group Egress Revoked' detects events where an egress rule in an AWS security group has been removed. Egress rules control the outbound traffic permissions for instances associated with specific security groups in a Virtual Private Cloud (VPC). By analyzing AWS CloudTrail logs, this detection rule utilizes Splunk logic to recognize the 'RevokeSecurityGroupEgress' event, indicating that the permission for instances to send traffic to specified IP addresses or other security groups has been rescinded. This action could potentially indicate unwanted changes to network policies, which might be the result of an insider threat, misconfiguration, or malicious activity. The detection processes CloudTrail logs to identify relevant attributes such as the time of the action, the user and account responsible, and the affected IP addresses. The rule emphasizes the importance of monitoring permissions and access management in order to maintain security in AWS deployments, particularly concerning the implications of revoked egress permissions that could affect communications.