Password synchronization is a function of certain identity management systems and it is considered easier to implement than enterprise single sign-on (SSO), as there is normally no client software deployment or need for active user enrollment.
[1] Since they only have to remember one or at most a few passwords, users are less likely to forget them or write them down, resulting in fewer calls to the IT Help Desk and less opportunity for coworkers, intruders or thieves to gain improper access.
Through suitable security awareness, automated policy enforcement and training activities, users can be encouraged or forced to choose stronger passwords as they have fewer to remember.
If the single, synchronized password is compromised (for example, if it is guessed, disclosed, determined by cryptanalysis from one of the systems, intercepted on an insecure communications path, or if the user is socially engineered into resetting it to a known value), all the systems that share that password are vulnerable to improper access.
Two processes which yields synchronized passwords are shown in the following animations, hosted by software vendor Hitachi ID Systems: 1