Linux Security Technologies
Linux Security Technologies
John Pierce
SELinux (Security Enhanced Linux) is a mandatory access control in the Linux kernel that was originally developed by NSA (National Security Agency) with direct contributions provided by Red Hat Enterprise Linux (RHEL) via the Fedora Project. In the day and age of identity theft and attempted sabotage from terrorists against our country, it should be very apparent why an organization like NSA had such an interest in heading up development of a more secure way to better protect our nation’s computer systems. In a world so largely dependent on computer systems, inadequate security measures could lead to anything from having a single person’s financial information compromised to an electronic 9/11 against some of our country’s most secure federal computer networks. In the modern computer based society we live in, security is essential to protecting everything from personal desktops all the way up to the most secure federal databases. And many corporate and government level computers are based on the Linux kernel. SELinux has 3 states it can be in if on a system: Enabled, Disabled, and Permissive. Enforcing means SELinux security policy is active, Disabled means SELinux security policy is not active, and Permissive is a diagnostic state commonly used for troubleshooting. To better understand what improvements Mandatory Access Control (MAC) can provide for security, one needs to know about the standard Linux security provision called Discretionary Access Control (DAC). DAC, though it is still a form of security, only provides minimal protection to a Linux file system. With DAC, access to files merely requires needed permissions from the owner of the file to access (commonly referred to as file permissions), often requiring a password to open. A basic weakness of DAC is not being able to fundamentally differentiate between human users and computer programs. And with so many systems often having such large
John Pierce
SELinux (Security Enhanced Linux) is a mandatory access control in the Linux kernel that was originally developed by NSA (National Security Agency) with direct contributions provided by Red Hat Enterprise Linux (RHEL) via the Fedora Project. In the day and age of identity theft and attempted sabotage from terrorists against our country, it should be very apparent why an organization like NSA had such an interest in heading up development of a more secure way to better protect our nation’s computer systems. In a world so largely dependent on computer systems, inadequate security measures could lead to anything from having a single person’s financial information compromised to an electronic 9/11 against some of our country’s most secure federal computer networks. In the modern computer based society we live in, security is essential to protecting everything from personal desktops all the way up to the most secure federal databases. And many corporate and government level computers are based on the Linux kernel. SELinux has 3 states it can be in if on a system: Enabled, Disabled, and Permissive. Enforcing means SELinux security policy is active, Disabled means SELinux security policy is not active, and Permissive is a diagnostic state commonly used for troubleshooting. To better understand what improvements Mandatory Access Control (MAC) can provide for security, one needs to know about the standard Linux security provision called Discretionary Access Control (DAC). DAC, though it is still a form of security, only provides minimal protection to a Linux file system. With DAC, access to files merely requires needed permissions from the owner of the file to access (commonly referred to as file permissions), often requiring a password to open. A basic weakness of DAC is not being able to fundamentally differentiate between human users and computer programs. And with so many systems often having such large