This analytic rule is designed to detect the creation of AWS Network Access Control Lists (ACLs) that allow all traffic from specified CIDR blocks, which poses significant security risks. Using AWS CloudTrail logs, the rule monitors specific API calls, namely `CreateNetworkAclEntry` and `ReplaceNetworkAclEntry`, filtering for actions where all ports are open. Such configurations are often indicative of potential vulnerabilities, as they can lead to unauthorized access, data breaches, or service disruptions. The detection logic involves checking for ACL entries that permit traffic based on protocol configurations, capturing activity related to network security policies in AWS environments. The implementation of this rule requires proper integration with Splunk's AWS App and add-on for real-time monitoring and alerting on critical network configuration changes that could compromise cloud security.