The Linux Intrusion Detection System (LIDS) is a patch which enhances the kernel's security by implementing a reference monitor and Mandatory Access Control (MAC). When it is in effect, chosen file access, all system/network administration operations, any capability use, raw device, memory, and I/O access can be made impossible even for root. You can define which programs can access specific files. It uses and extends the system capabilities bounding set to control the whole system and adds some network and filesystem security features to the kernel to enhance the security. You can finely tune the security protections online, hide sensitive processes, receive security alerts through the network, and more.
The main goal of the Linux Trustees project is to create an advanced permission management system for Linux. The solution proposed is mainly inspired by the approach taken by Novell Netware and the Java security API. Special objects (called trustees) can be bound to every file or directory. The trustee object can be used to ensure that access to a file, directory, or directory with subdirectories is granted (or denied) to a certain user or group (or all except user or group). Trustees are like POSIX ACLs, but trustee objects can affect entire subdirectory trees, while ACLs a single file. Trustees works with the 2.6 Linux kernel.
Logcheck Consolidator is a utility which manages the log files from multiple computers to help you keep track of your network. It takes logcheck e-mail and parses it for each of your systems into one piece of mail. It has a lot of built-in logic. For example, if a host does not send its hourly e-mail, the logcheck consolidator will notice this and flag it as an error at the top of the consolidated e-mail.
LOMAC uses Low Water-Mark Mandatory Access Control to protect the integrity of processes and data from viruses, trojan horses, malicious remote users, and compromised network server daemons. The LOMAC loadable kernel module can be used to harden Linux systems without any changes to existing kernels, applications, or configuration files. Due to its simplicity, LOMAC itself requires no configuration, regardless of the users and applications present on the system. Although some features and fixes remain to be implemented, LOMAC presently provides sufficient protection to thwart some attacks, and is stable enough for everyday use.
Mason is a tool that interactively builds a firewall using Linux' ipfwadm or ipchains firewalling. You leave mason running on the firewall machine while you are making all the kinds of connections that you want the firewall to support (and want it to block). Mason gives you a list of firewall rules that exactly allow and block those connections. It can either build a firewall from scratch for you or supplement an existing firewall.
mcrypt is a program for encrypting files or streams. It is intended to be a replacement for the old UNIX crypt. It uses well-known and well-tested algorithms like BLOWFISH, AES, ARCFOUR, CAST-128, and more in several modes of operation. It also has a compatibility mode with the old UNIX crypt program and the des program found in Solaris.