There was a sudden unusual peak of outbound traffic from my hosted dedicated server (OS - Windows Server 2008 R2). The hoster threatened to block the server if the problem is not solved.
There are an ASP.NET MVC application and a SQL Server 2008 Express database installed on the server.
After that I've installed all missing security patches, changed and hardened passwords, scanned the server with Microsoft Malicious Software Removal Tool (nothing found). But I don't feel the problem is solved.
What should be done in such a case?