AppArmor For Health Data Access Control: Assessing Risks and Benefits

The AppArmor Linux Security Module (LSM) is widely used on Linux operating systems as it, among other things, provides mandatory access control (MAC) and isolates processes. This isolation helps meet the privacy requirements for critical applications. These application security policies are defined with profiles loaded into the Linux system kernel. However, these access control mechanisms are far from covering all the rising demands for confidentiality enforcement regarding critical applications. This paper conducts a risks and benefits analysis to assess whether a healthcare infrastructure can safely rely on the AppArmor LSM to protect its sensitive data. Thus, the general architecture of AppAmor comes to be detailed. Then, a static code analysis is performed to study the data structures found in the LSM. Finally, the outbreak of would-be side-channel attacks from userspace is discussed while offering mitigation methods. The result of this analysis shows that the AppArmor LSM is susceptible to side-channel attacks and should be used as part of a more comprehensive defense-in-depth strategy.