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Support for Iterators in SQL Server 2022 Password Validation

Michael Howard has an update for us:

We all know that as security threats evolve, we must update our defenses to mitigate newer threats. Over the last few months, some customers have asked us to strengthen the way we secure passwords in SQL Server. The most often-cited reference by customers is to comply with NIST SP 800-63b.

Currently supported versions of SQL Server and Azure SQL DB use a SHA-512 hash with a 32-bit random and unique salt. It is statistically infeasible for an attacker to deduce the password knowing just the hash and the salt. It is considerably easier for an attacker to hunt for insecure storage of database connection strings that contain database credentials than it is to break the password verifier (also called a password authenticator) used by SQL Server and Azure SQL DB. But that’s a discussion for another day and is the main reason we highly recommend using Entra ID authentication rather than using uid/pwd-based connections because Entra ID authentication manages credentials and supports access policies.

Michael gives you an idea as well of why iterators are valuable and how you can tell if your SQL authenticated accounts are using this new setup.

I’m curious how much of an effect this will have on login time. Typically, using PBKDF (or PBKDF2) does increase login time by a couple hundred milliseconds—which is the entire point of the exercise, ensuring that an attacker cannot feasibly brute force passwords in reasonable time—so I would not expect the difference to be too noticeable. For a really busy system, however, I could see some small impact.