User Security Tools provides some improvements to security in wordpress.
Control for Brute Force: Adds a maximum of failed login attempts within a certain period of
time. If this maximum is achieved, the user is locked.
Password Policy: Enforces the minimun and maximum length of the password, and the level of
password that can be: low, medium and high.
Password History: Don’t allow user to set password equals last 5 (in the next version this number
will be configurable).
User Management: the network admin also can lock, unlock and reset user’s password manually
(in case of password reset, the user receives a new activation key and no data is lost).