In computer security, the Linux Intrusion Detection System (LIDS) was a patch to the Linux kernel and associated administrative tools that enhanced the kernel's security by implementing mandatory access control (MAC). When LIDS was in effect all system network administration operations, chosen file access, any capability use, raw device, memory, and I/O access could be made impossible, even for root. One could define which programs can access specific files. It used and extended the system capabilities bounding set to control the whole system and added some network and filesystem security features to the kernel to enhance the security. One could finely tune the security protections online, hide sensitive processes, receive security alerts through the network, and more. LIDS supported Linux kernel 2.6, 2.4. LIDS was released under the terms of the GNU General Public License (GPL).