Requirement
- Enforce a limit of [Assignment: organization-defined number] consecutive invalid logon attempts by a user during a [Assignment: organization-defined time period].
- Automatically [Selection (one or more): lock the account or node for an [Assignment: organization-defined time period]; lock the account or node until released by an administrator; delay next logon prompt; notify system administrator; take other action] when the maximum number of unsuccessful attempts is exceeded.
Explanation
Due to the potential for denial of service, automatic system lockouts are in most cases, temporary and automatically release after a predetermined time period established by the organization (i.e., using a delay algorithm). Organizations may employ different delay algorithms for different system components based on the capabilities of the respective components. Responses to unsuccessful system logon attempts may be implemented at the system and application levels.
Organization-defined actions that may be taken include prompting the user to answer a secret question in addition to the username and password, invoking a lockdown mode with limited user capabilities (instead of a full lockout), allowing users to only logon from specified Internet Protocol (IP) addresses, requiring a CAPTCHA to prevent automated attacks, or applying user profiles, such as location, time of day, IP address, device, or Media Access Control (MAC) address.
