pwdump is the name of various Windows programs that output the LM and NTLM password hashes of local user accounts from the Security Account Manager (SAM). In order to work, it must be run under an Administrator account, or be able to access an Administrator account on the computer where the hashes are to be dumped; so pwdump does not compromise security.
Please note that you will require pwdump when using Ophcrack - a tool to crack Windows passwords.
http://en.wikipedia.org/wiki/Pwdump
