Information
The Junos default behavior for login security provides reasonable protection from password guessing attacks, but may not be suitable for every environment.
Limit the minimum length of time in seconds that the connection remains open while the user is attempting to enter a password to log in. The range is from 20 through 60. The default setting is 20.
Solution
Configure login security for minimum amount of time a login attempt has before disconnect.
user@host# edit system login retry-options
user@host# set minimum-time 15