A company's two-tier image processing application, deployed across two Availability Zones with distinct public and private subnets, is experiencing performance issues due to a high volume of illegitimate requests from specific IP addresses. The web tier, served by an Application Load Balancer in public subnets, and the application tier, hosted on EC2 instances in private subnets, require an immediate solution to mitigate this impact. What action should a solutions architect take to address the current slowdown while a long-term fix is explored?