Metrics install automatically if you have Redgate Monitor installed.
If you are using Redgate’s SQL Server monitoring tool, Redgate Monitor, you can instantly install and run this metric on your servers.
This custom metric queries the default trace to find events related to creation of new Server Logins
Metric definition
Name
New Server Login Added
Description
This custom metric queries the default trace to find events related to creation of new Server Logins
The T-SQL query that will collect data
Instances to collect from
Select All
Databases to collect from
Master
Collection frequency
60
Use collected or calculated values
Leave the Use a calculated rate of change between collections check box unchecked
Metric collection
Enabled
Alert definition
You could add an alert once the baseline for your environment has been established.