Assessing the Tux Strength: Part 2 – Into the Kernel

“The previous article in this series on Linux security described
different userspace protection mechanisms that can be applied to
protect binaries on a Linux system. Unsurprisingly, without
additional kernel settings and protections most of the previously
described mechanisms cannot be utilised to their full extent. This
article will therefore focus on kernel features that have a direct
impact on security of running binaries. Specific security
frameworks such as SELinux, Grsecurity RBAC, AppArmor and others
will not be discussed here although they may feature in future
articles.

“Most of the kernel features described here will be related to
the addition of protection within userspace; however, a few of them
will also have a direct impact on the security of the kernel
itself. The security of the kernel is also very important as once
an attacker is able to execute their own code in the kernel space
there’s very little that can be done to maintain the security of
the system. The Linux kernel is subject to rapid development with
many new features being added or existing functionality being
amended and support for new devices is added on a regular basis. It
should be noted that the direct and indirect impact of these issues
on the security of the kernel can be easily overlooked. It is also
not uncommon for a security feature that is enabled in the kernel
to have an impact on its performance and the overall performance of
the system as well.”

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