How to prevent a user from using the sticky key command from exposing the command prompt without logging in.

First off, several things would have to fail before this vulnerability is exposed. The organization in question would not be following the Defense-in-Depth concept that we discussed listed below. In particular, the first level “Policies, Procedures, & Awareness” would not be followed.

In order to be able to change the Sethc.exe file, the user would have to both take ownership and give themselves rights to this application. A standard user account cannot do this. If the users are given local admin rights, this vulnerability could be exploited. By copying the CMD.EXE application and remaining it to Sethc.exe, a command prompt could be brought up under the system context without a user logging in.

For your IT Staff, a rogue member could easily exploit this vulnerability. To prevent this from happening, execute the procedure on this link to remove the user’s ability to use a command prompt. The key to this is the Software Restriction Policy. Since it is created using a hash, changing the name and location of the CMD.EXE file will still not allow the user to run it. Be careful not to apply this policy to those who actually need to use a command prompt. You may want to keep this policy on the client machines to help prevent standard users from working outside their job descriptions. Also, on the servers but for only the IT staff who do not need to use a command prompt.

Reference:
http://aplawson.wordpress.com/2009/04/22/pentest-sticky-keys-sethcexe-vulnerability-in-2003-xp-vista/

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