What protocols are used by the CASB Securlets and how the connection from the CASB to the SaaS is secured?
Securlets is a Data-at-Rest solution that allows CloudSOC to connect to various cloud services using the vendors API.
Vendor such as o365 provide the security such as TLS 1.2 and a OAuth token where the vendor renews the auth token.
The Securlet documentation will point out the API's used. o365 API USED. The vendors documentation will provide the security requirements as each vendor will be different.