Description: The default policy in SELinux is the basic security configuration applied to an operating system to control access to resources and protect the integrity of the system. This policy defines which processes can access which files and resources, establishing a framework for access control that helps prevent unauthorized actions. The default policy is based on the principle of least privilege, meaning that processes only have access to the resources they need to function, thereby minimizing the risk of compromising the system. Additionally, this policy can be customized and adjusted according to the specific security needs of various environments, allowing system administrators to tailor access rules to their requirements. Implementing an effective default policy is crucial for maintaining security in systems that handle sensitive data or are exposed to external threats, as it provides a first line of defense against attacks and vulnerabilities.
History: SELinux was developed by the National Security Agency (NSA) of the United States in the 2000s as part of an effort to enhance the security of Linux-based operating systems. The default policy was introduced as a way to establish a basic set of security rules that could be applied across different environments, facilitating the implementation of stricter access controls. Over time, SELinux has evolved and become a fundamental tool for security in Linux systems, being adopted by various distributions.
Uses: The default policy of SELinux is primarily used in environments where security is a priority, such as web servers, databases, and systems handling sensitive information. It allows administrators to define and enforce access rules that protect system resources, ensuring that only authorized processes can interact with them. This is particularly useful in multi-user environments or in systems that require a high level of security.
Examples: An example of a default policy in SELinux is the ‘targeted’ policy, which is applied in many Linux distributions. This policy allows most processes to run with normal access while specifically restricting those considered high-risk, such as database servers or web applications. Another example is the ‘strict’ policy, which applies more stringent access controls to all system processes, ideal for environments requiring an extreme level of security.
