Preventing Denial-of-Service Attacks on a P-Kernel for WebOSes

• Authors: J. Liedtke;N. Islam;T. Jaeger
• Venue: HOTOS '97 Proceedings of the 6th Workshop on Hot Topics in Operating Systems (HotOS-VI)
• Year: 1997

A goal of World Wide Web operating systems (WebOSes) is to enable clients to download executable content from servers connected to the World Wide Web (WWW). This will make applications more easily available to clients, but some of these applications may be malicious. Thus, a WebOS must be able to control the downloaded content's behavior. We examine a specific type of malicious activity: denial of service attacks using legal system operations. A denial of service attack occurs when an attacker prevents other users from performing their authorized operations. Even when the attacker may not be able to perform such operations. Current systems either do little to prevent denial of service attacks or have a limited scope of prevention of such attacks. For a WebOS, however, the ability to prevent denial of service should be an integral part of the system. We are developing a WebOS using the L4 /spl mu/ kernel as its substrate. We evaluate L4 as a basis of a system that can prevent denial of service attacks. In particular, we identify the /spl mu/ kernel related resources which are subject to denial of service attacks and define /spl mu/ kernel mechanisms to defend against such attacks. Our analysis demonstrates that system resource utilization can be managed by trusted user level servers to prevent denial of service attacks on such resources.