Biblio

An important principle in computational security is to reduce the attack surface, by maintaining the Trusted Computing Base (TCB) small. Even so, no security technique ensures full protection against any adversary. Thus, sensitive applications should be designed with several layers of protection so that, even if a layer might be violated, sensitive content will not be compromised. In 2015, Intel released the Software Guard Extensions (SGX) technology in its processors. This mechanism allows applications to allocate enclaves, which are private memory regions that can hold code and data. Other applications and even privileged code, like the OS kernel and the BIOS, are not able to access enclaves' contents. This paper presents a novel password file protection scheme, which uses Intel SGX to protect authentication credentials in the PAM authentication framework, commonly used in UNIX systems. We defined and implemented an SGX-enabled version of the pam\_unix.so authentication module, called UniSGX. This module uses an SGX enclave to handle the credentials informed by the user and to check them against the password file. To add an extra security layer, the password file is stored using SGX sealing. A threat model was proposed to assess the security of the proposed solution. The obtained results show that the proposed solution is secure against the threat model considered, and that its performance overhead is acceptable from the user point of view. The scheme presented here is also suitable to other authentication frameworks.

Eduroam is a secure WLAN roaming service between academic and research institutions around the globe. It allows users from participating institutions secure Internet access at any other participating visited institution using their home credentials. The authentication credentials are verified by the home institution, while authorization is done by the visited institution. The user receives an IP address in the range of the visited institution, and accesses the Internet through the firewall and proxy servers of the visited institution. However, access granted to services that authorize via an IP address of the visited institution may include access to services that are not allowed at the home institution, due to legal agreements. This paper looks at typical legal agreements with service providers and explores the risks and countermeasures that need to be considered when using eduroam.