Machines using the SQL Authentication I have a requirement. The leadership wants an email list of all the users hitting the database and last access date. I have created the script that has the username and the time accessed. The issue is with SQL authentication. SQL authentication is only given to applications and the application accesses the database. The leadership wants me to design something that goes in and finds out the Active directory username for this SQL authentications hitting the database. I personally do not think this is achievable in SQL however, I would like to take the opinion of the community. Please advise.
As you identified in your question, it is not possible to reliably discern which Windows user is logged into a SQL Server using a SQL Server login.  You could track the name of the workstation where the user connects from, but that doesn't guarantee anything - the workstation name is easily spoofed.

If you require that level of auditing, you'd need to build it into all applications accessing the database.