Various embodiments of the invention disclosed herein provide techniques for mitigating a distributed denial of service (DDoS) attack on a targeted computer system. A border gateway protocol (BGP) controller receives, via a first router, a BGP message that includes an indicator indicating that a computer system associated with the first router is under a DDoS attack. In response to receiving the BGP message, the BGP controller, in performs one or more operations to mitigate the DDoS attack. As a result, the time between detection of a DDoS attack and mitigating the attack is reduced relative to prior approaches. After receiving the BGP message indicating a DDoS attack is in progress, the DDoS attack mitigation platform automatically takes steps to mitigate the DDoS attack without further manual intervention. Consequently, the targeted computer system recovers more quickly and begins to respond to legitimate network requests sooner relative to prior approaches.