1. A method of changing a user password on a target system, the method comprising: receiving a first request from a user at an access control system to change a user password of the user for a target system to a new password; storing at the access control system the new password; changing, by the access control system, the user password on the target system to the new password; receiving, at the access control system, a second request from the target system to grant access to a sensitive resource at the target system to the user, the second request responsive to a prior request received at the target system from the user for access to the sensitive resource, the prior request including an input user password and wherein the second request includes information associated with the input user password; comparing, by the access control system, the information associated with the input user password and the stored new password; and responsive to a determination by the access control system that the information associated with the input user password is not consistent with the stored new password, denying access to the sensitive resource to the user.