XP_CmdShell Default Proxy

Most DBAs don’t think of it, but xp_cmdshell has a
default proxy account. In fact, this proxy is responsible for its permissions, and actually follows Microsoft’s current external script security strategy. So xp_cmdshell isn’t unique and it doesn’t do anything special security-wise.
Here you’ll see how to test which credentials xp_cmdshell is using. It’s actually pretty easy.