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Public-facing front-end servers, like web servers for e-commerce companies or universities, often use shared infrastructure and software in order to support thousands of users. Unfortunately, this shared infrastructure provides an opportunity for attackers: a malicious client can find a vulnerability in the server's software and exploit it to attack other users and to implant malicious software that will attack future visitors.
These front-end servers often have highly elevated privileges in order to serve a variety of users, from customers, to merchants, to the employees that administer the site itself. But, since it is exceedingly difficult to write defect-free code, these same servers often have vulnerabilities that can be exploited by an attacker. The attackers can thus manipulate these servers into using their elevated privileges for malicious purposes, which is known as a "confused deputy" attack.
In our research, we seek to eliminate confused deputy attacks and the ability for a malicious client to affect others. We do so by eliminating the shared infrastructure associated with these public-facing servers. Rather than provide a single server that many clients use, we create a unique, single-use server for each client. While such an approach would be infeasible with physical infrastructure and prohibitively costly even with virtual machines, we can use lightweight containerization technology to isolate each instance of a public-facing server. When a client ends its session, we simply discard the container, eliminating the ability for an attacker to implant code that will affect future users. Finally, the single-use technique allows us to customize the permissions associated with each container, avoiding the need for highly-elevated privileges that enable the confused deputy attack.
When complete, we expect to have results showing the viability of a single-use server approach even for high-volume public-facing servers. We also will demonstrate how existing application servers can be inserted into such a system with minimal changes.
This project is described in a press release from WPI as well as in the following video that demonstrates how the technology works.
The source code for the SuS project is available as a .zip file. A video tutorial and text based tutorial describe how to install our Single-Use Servers system for the WordPress content management tool.
This material is based upon work supported by the National Science Foundation under Grant No. 1814402. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.