Redmine

When a user account is created by an administrator, a plain-text password is sent over the network. Users should be forced to change their passwords in this situation, but there is currently no means by which to enforce this.

The standard way to enforce this is to expire user passwords when they first log into the system so that they must change their passwords. This way, if anyone else digs up a user's initial password later and tries to use it, it will be useless.