In the CCS Installation Guide (v10.5), installing the R&A in distributed setup mode, is the user name and password provided in the "Use a SQL user name and password" stored by CCS (maybe in the ADAM/ADLDS?).
In page 117 of the manual, step 10:
The SQL server information is used to create the production database on the
Application Server computer that stores the CCS data
Most of the time 'sa' is the primary candidate here.
What is the account then used as CCS reads and write data to the CSM_DB, Evidence, and Reporting DB?