Mitigating DoS Attacks Using Performance Model-Driven Adaptive Algorithms

Abstract

Denial of Service (DoS) attacks overwhelm online services, preventing legitimate users from accessing a service, often with impact on revenue or consumer trust. Approaches exist to filter network-level attacks, but application-level attacks are harder to detect at the firewall. Filtering at this level can be computationally expensive and difficult to scale, while still producing false positives that block legitimate users.This article presents a model-based adaptive architecture and algorithm for detecting DoS attacks at the web application level and mitigating them. Using a performance model to predict the impact of arriving requests, a decision engine adaptively generates rules for filtering traffic and sending suspicious traffic for further review, where the end user is given the opportunity to demonstrate they are a legitimate user. If no legitimate user responds to the challenge, the request is dropped. Experiments performed on a scalable implementation demonstrate effective mitigation of attacks launched using a real-world DoS attack tool. ACM Reference Format:Barna, C., Shtern, M., Smit, M., Tzerpos, V., and Litoiu, M. 2014. Mitigating DoS attacks using performance model-driven adaptive algorithms.

Challenges in Composing and Decomposing Assurances for Self-Adaptive Systems

“…These models are used at design time to determine initial resource provisioning given assumptions about the environment, and at run time to determine correct provisioning to new workflows and configurations. A similar approach is used [2] to deal with Denial of Service attacks, where performance models are used to determine whether to divert traffic to a checkpoint, which then issues a challenge to determine if the traffic originates from a bot. In this case the soundness of the mathematical models and their updating and use at run time provide evidence that performance goals will be met.…”

“…If we assure the system under one variant of the dispatcher but later compose our system using a different variant of the dispatcher, the original assurances may not hold. This problem can occur in all three types of composition (1)(2)(3). This dynamic view of composition leads to a new level of complexity and may require a new argumentation structure; one that was not considered during decomposition.…”