80 lines
4.1 KiB
Text
80 lines
4.1 KiB
Text
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=== Password guess: brute force attacks
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A brute force attack happens when an attacker is trying to guess a user's password.
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{project_name} has some limited brute force detection capabilities.
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If turned on, a user account will be temporarily disabled if a threshold of login failures is reached.
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To enable this feature go to the `Realm Settings` left menu item, click on the `Security Defenses` tab, then additional
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go to the `Brute Force Detection` sub-tab.
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NOTE: Brute Force Detection is disabled by default. Enabling this feature is highly recommended to protect against this type of attack.
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.Brute Force Detection
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image:{project_images}/brute-force.png[]
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There are 2 different configurations for brute force detection; permanent lockout and temporary lockout. Permanent lockout will disable a user's account after an attack is detected; the account will be disabled until an administrator renables it. Temporary lockout will disable a user's account for a time period after an attack is detected; the time period for which the account is disabled increases the longer the attack continues.
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*Common Parameters*
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====
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Max Login Failures::
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Maximum number of login failures permitted. Default value is 30.
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Quick Login Check Milli Seconds::
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Minimum time required between login attempts. Default is 1000.
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Minimum Quick Login Wait::
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Minimum amount of time the user will be temporarily disabled if logins attempts are quicker than _Quick Login Check Milli Seconds_. Default is 1 minute.
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====
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*Temporary Lockout Parameters*
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====
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Wait Increment::
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Amount of time added to the time a user is temporarily disabled after each time _Max Login Failures_ is reached. Default is 1 minute.
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Max Wait::
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The maximum amount of time for which a user will be temporarily disabled. Default is 15 minutes.
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Failure Reset Time::
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Time after which the failure count will be reset; timer runs from the last failed login. Default is 12 hours.
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====
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*Permanent Lockout Algorithm*
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====
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. On successful login
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.. Reset `count`
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. On failed login
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.. Increment `count`
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.. If `count` greater than _Max Login Failures_
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... Permanently disable user
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.. Else if time between this failure and the last failure is less than _Quick Login Check Milli Seconds_
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... Temporarily disable user for _Minimum Quick Login Wait_
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When a user is disabled they can not login until an administrator enables the user; enabling an account resets `count`.
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====
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*Temporary Lockout Algorithm*
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====
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. On successful login
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.. Reset `count`
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. On failed login
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.. If time between this failure and the last failure is greater than _Failure Reset Time_
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... Reset `count`
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.. Increment `count`
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.. Calculate `wait` using _Wait Increment_ * (`count` / _Max Login Failures_). The division is an integer division so will always be rounded down to a whole number
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.. If `wait` equals 0 and time between this failure and the last failure is less than _Quick Login Check Milli Seconds_ then set `wait` to _Minimum Quick Login Wait_ instead
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... Temporarily disable the user for the smaller of `wait` and _Max Wait_ seconds
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Login failures when a user is temporarily disabled do not increment `count`.
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====
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The downside of {project_name} brute force detection is that the server becomes vulnerable to denial of service attacks.
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An attacker can simply try to guess passwords for any accounts it knows and these account will be disabled.
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Eventually we will expand this functionality to take client IP address into account when deciding whether to block a user.
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A better option might be a tool like http://www.fail2ban.org/wiki/index.php/Main_Page[Fail2Ban]. You can point this service at the {project_name} server's log file.
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{project_name} logs every login failure and client IP address that had the failure. Fail2Ban can be used to modify
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firewalls after it detects an attack to block connections from specific IP addresses.
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==== Password Policies
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Another thing you should do to prevent password guess is to have a complex enough password policy to ensure that
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users pick hard to guess passwords. See the <<_password-policies, Password Policies>> chapter for more details.
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The best way to prevent password guessing though is to set up the server to use a one-time-password (OTP).
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