> every employee can access our main financial/back office SQL database
This means that there is no access gate other than RLS, which includes financial data. That is a lot of pressure on one control.
RLS has been around a long time and is very stable and doesn't change much. SSO providers keep adding stuff ALL the time, and they regularly have issues. PG RLS is very boring in comparison.
I don't remember the last CVE or outage we had with PG that broke stuff. I can't remember a single instance of RLS causing us access control problems on a wide scale. Since we tied their job(s) to their access control many years ago, it's very rare that we even have the random fat-fingered access control issue for a single user anymore either. I think the last one was a year ago?
Some do, which is why they want MFA on the target side as well as on their SSO. But yes, SSO is very scary and there's a ton of security pressure on it. I don't think that's a very good argument for why we should think that every system should only require one layer of defense.
I'm going to sort of skip over any comparison to SSO since I'm not going to defend the position of "SSO is fine as a single barrier", especially as SSO is rarely implemented with one policy - there's device attestation, 2FA, etc.
> RLS has been around a long time and is very stable and doesn't change much.
RLS is great, I'm a fan.
> I don't remember the last CVE or outage we had with PG that broke stuff.
It doesn't really matter. The fact is that you're one CVE away from every employee having access to arbitrary data, including financial data. I feel a bit like a broken record saying this.
Sure, but it's the same with pretty much any other app architecture.
Either your app has all the data access and you put your access control there, or you do the access control in the database. There really aren't other options here. There isn't access control defense in depth here. The best you can really do is do some data encryption of the data in the tables. We do some of that, but it's such a PITA that we relegate it to special stuff only.
> especially as SSO is rarely implemented with one policy - there's device attestation, 2FA, etc.
Sure but ALL of that relies on the SSO system behaving as advertised, so you think of it as separate policies, but it really isn't. It's once SSO CVE away from giving away the store. We use SSO with PG, that's how they authenticate to PG, we are fans of SSO too.