The .NET Developer's Guide to Windows Security

Chapter 31. What Is Impersonation?

Impersonation is one of the most useful mechanisms in Windows security. It's also fragile and easy to misuse. Careful use of impersonation can lead to a secure, easy-to-administer application. Misuse can open gaping security holes.

After an application authenticates a user, the application can take on that user's identity through impersonation. Impersonation happens on a thread-by-thread basis to allow for concurrency, which is important for multithreaded servers as each thread might be servicing a different client. In Figure 31.1, the server process is configured to run as Bob. It contains five threads, two of which are impersonating in order to do work on behalf of authenticated clients.

Figure 31.1. Impersonation ...