Cloud API Call to Rarely Used Geographic Region

This rule detects HTTP traffic where the host header contains specific cloud region identifiers that are considered rarely used. The rule is triggered if 10 such events occur within 60 seconds from the same source IP address. The identified regions are 'ap-east-1', 'me-south-1', 'af-south-1', and 'eu-south-1'. This could indicate an attempt to evade detection by using less common cloud infrastructure or an unauthorized API call from an unusual geographic location.