Description: The ‘Security Domain’ in the context of computer security refers to a set of objects and subjects that share a common security policy. In this framework, ‘subjects’ are entities that can perform actions, such as processes or users, while ‘objects’ are resources on which actions can be performed, such as files, sockets, or devices. The security policy defines the rules that determine which subjects can access which objects and under what conditions. This approach allows for granular control over permissions, meaning specific restrictions can be set for each subject and object, thereby enhancing system security. Security labels are used to classify these subjects and objects, facilitating the implementation of more complex and secure access policies. This security model is essential for protecting critical and sensitive systems, as it minimizes the risk of unauthorized access and potential vulnerabilities. In summary, the ‘Security Domain’ is a structure that organizes and regulates access to system resources, ensuring that only authorized subjects can interact with permitted objects, all under a well-defined security policy framework.
History: SELinux was developed by the United States National Security Agency (NSA) in the 2000s as part of an effort to enhance the security of Linux-based operating systems. Its design is based on the mandatory access control (MAC) model, which was introduced to provide a level of security beyond traditional access controls. Over the years, SELinux has evolved and been integrated into various Linux distributions, becoming a standard for security in critical systems.
Uses: SELinux is primarily used in environments where security is a priority, such as web servers, databases, and sensitive information systems. It allows administrators to define security policies that control access to critical resources, thereby protecting systems from attacks and unauthorized access. Additionally, it is used in mobile devices and embedded systems to ensure the integrity and confidentiality of data.
Examples: A practical example of SELinux in action is its implementation in application servers handling sensitive data, such as those used in the financial sector. In these cases, SELinux can restrict access to configuration files and databases, ensuring that only authorized processes can interact with them. Another example is its use in various operating systems, where security policies protect the system and applications from unauthorized access.
