Getting Started with the Linux Intrusion Detection System
For MySQL, we need to deny other applications' access to the mysql binary. We also need to restrict access to the mysql/var directory so that it's append=only, and allow read-only access for the mysqld dæmon to the mysql directory:
lidsconf -A -o /usr/local/mysql/var -j APPEND lidsconf -A -o /usr/local/mysql -j DENY lidsconf -A -s /usr/local/mysql/libexec/mysqld -o /usr/local/mysql -j READONLY lidsconf -A -s /usr/local/mysql/libexec/mysqld -o /usr/local/mysql/var -j WRITE
Bind needs a lot of capabilities to run:
lidsconf -A -s /usr/sbin/named -o CAP_NET_BIND_SERVICE 53 -j GRANT lidsconf -A -s /usr/sbin/named -o CAP_SETPCAP -j GRANT lidsconf -A -s /usr/sbin/named -o CAP_SYS_CHROOT -j GRANT lidsconf -A -s /usr/sbin/named -o CAP_SYS_RESOURCE -j GRANT lidsconf -A -s /usr/sbin/named -o CAP_SETUID -j GRANT lidsconf -A -s /usr/sbin/named -o CAP_SETGID -j GRANT
Login is the program that allows a user to log in to a GNU/Linux system:
lidsconf -A -s /bin/login -o /etc/shadow -j READONLY lidsconf -A -s /bin/login -o CAP_SETUID -j GRANT lidsconf -A -s /bin/login -o CAP_SETGID -j GRANT lidsconf -A -s /bin/login -o CAP_CHOWN -j GRANT lidsconf -A -s /bin/login -o CAP_FSETID -j GRANT
After having specified the previous commands, we need to seal the kernel, so that the system can take full advantage of LIDS. We add this line to rc.local:
Restart the machine to apply all the new access controls. With the previously mentioned access controls, you will not be able to run the X server as it uses raw I/O, but most servers don't run an X server anyway. If you really need it, add the following access control (this command assumes that your X server binary is located in /usr/X11R6/bin/startx):
lidsconf -A -s /usr/X11R6/bin/startx
As we can see, LIDS is a powerful addition to the Linux kernel, which can secure your system completely, even from the root user. LIDS is also very easy to use.
Irfan Habib is a software engineering student at the National University of Science and Technology in Pakistan. He has had great interest in Linux and open-source technology since high school—everything from embedded Linux development to Web services. He has been advocating GNU/Linux in Pakistan for the past two years and has written various articles in local magazines and newspapers on the subject.
Free DevOps eBooks, Videos, and more!
Regardless of where you are in your DevOps process, Linux Journal can help!
We offer here the DEFINITIVE DevOps for Dummies, a mobile Application Development Primer, and advice & help from the expert sources like:
- Linux Journal
- New Products
- Flexible Access Control with Squid Proxy
- Users, Permissions and Multitenant Sites
- Security in Three Ds: Detect, Decide and Deny
- Solving ODEs on Linux
- Tighten Up SSH
- High-Availability Storage with HA-LVM
- DevOps: Everything You Need to Know
- Non-Linux FOSS: MenuMeters
- Android Candy: Bluetooth Auto Connect