The AWS VPC SSH Allowed Signal rule analyzes inbound traffic on SSH port 22 in AWS VPC Flow Logs. The purpose of this rule is to detect legitimate SSH traffic that is allowed from public IPs to private IPs. It serves as a preliminary indicator that could be used in further correlation rules to investigate potential unauthorized access attempts. The rule is tagged as an informational signal, meaning it does not trigger alerts on its own but can provide valuable context when analyzed with other events. Overall, it is a crucial component in monitoring network traffic for unusual patterns concerning SSH access in cloud environments, contributing to a better security posture against unauthorized intrusions.