The Everyone group should not have more than Read access to the SQL registry keys. For example, if an unauthorized person has write access to the registry, they could change the authentication type for your server from Windows Authentication to Mixed mode, and use this change to try to gain access to your system through the sa account (system administrator). If a blank or weak password was assigned to that account, the unauthorized person could log on as system administrator.
Ensure that the Everyone group is restricted to Read access for the SQL Server registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\MICROSOFT SQL SERVER
HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\MSSQLSERVER
Microsoft SQL Server 2000 Security
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