How is Authentication Between marketing cloud and sales cloud handled from Custom Preference Center

Question

In our company a 3rd party vendor group created a single page that has combination of amp script and SSJS for custom preference center. From a security stand point, I was trying to figure out how authentication is handled to make call to our sales cloud instance. In the code i don't see any usage of any tokens(No oauth related info).

My question is what are the different ways of handling authentication from custom preference center?(Do they use the connected app used for data extension?)

NOTE: I cannot post our code because of security reasons(I wish i could).

Answer 1

If your account is using Marketing Cloud Connect which it sounds like it is the authentication is handled automatically between the two clouds.

see: https://help.salesforce.com/articleView?id=mc_co_authentication.htm&type=5

The Ampscript and SSJS code on the preference page will have special functions to update records in sales/service clouds without having to explicitly set any authentication tokens etc in the Ampscript or SSJS itself.