mssqlshell: switch back to current db after enum_impersonate

[exploide]

When running enum_impersonate in the SQL shell, it will cycle through all available databases and remains in the last one. This is unexpected because it silently changes the current database. The following screenshot illustrates the issue.

This change ensures the current database after running enum_impersonate is the same as before.

[gabrielg5]

Hi @exploide , nice catch! thanks for the PR
I just made a couple suggestions in case an exception is triggered in the enum_impersonate.

Let me know what you think, and we can move forward with the merge

[exploide]

Hi @gabrielg5 thank you very much for your review!

That the function might raise an exception and the db change is not performed is a valid concern. Unfortunately the change you committed did not solve the problem because when it's done in the except clause, the db change will only be performed when an exception occurred, but not when everything went well. So it needs to go into a finally clause instead. I changed that now.

(I did not wrap the db change in another try/catch again because I assume it is simple enough and some other functions like do_enum_users don't do it as well. But yeah, it is a bit inconsistent. On the other hand, catching a bare exception might be problematic anyway, because it could silently hide errors. But this is a code style question and might be out of scope of this PR. I can change it though if you like.)

Feel free to move forward with the merge or request changes. :)

[gabrielg5]

hey, yes! my intention was to put it in the finally clause, but ended up putting it in the except :/
testing now, if all good will merge it
thanks!!