Logging and Triangulation

Track the source IP address of authentication attempts for an account. The specific IP address of a user can change due to proxies, time of day, travel, or other legitimate reasons. However, the IP address used to access the login page for an account should remain static during the brief login process and is very unlikely to hop geographic regions during failure attempts.

This method correlates login attempts for an account with the source IP of the request. If an IP address is hopping between class B addresses during a short period of time (a minute, for example), that behavior is a strong indicator of a brute force attack.

In addition, if successful authentication attempts occur contemporaneously or within a small ...

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