ElastiCache cluster is using the default subnet group

Description

ElastiCache is a fully managed, in-memory data store service that provides high-performance and scalable caching solutions in the cloud. An ElastiCache cluster is a collection of one or more cache nodes that work together to provide high performance and scalable caching of data in-memory. When launching an ElastiCache cluster, a default subnet group is created if one doesn't exist already. The default group uses subnets from the default Virtual Private Cloud (VPC), which may contain resources that are not part of the ElastiCache cluster's intended network environment. This can make it easier for attackers to discover the ElastiCache cluster and potentially exploit vulnerabilities in its configuration or software to gain unauthorized access. It was detected that the ElastiCache cluster {AwsElasticacheRedisCluster} is using the default subnet group. It is advised to use custom subnet groups that are more restrictive of the subnets that the cluster resides in, and the networking that the cluster inherits from the subnets.