Brad Spengler, the developer behind the Grsecurity project, has published an exploit for a vulnerability in the Tun interface in Linux kernel 2.6.30 and 2.6.18, used in Red Hat Enterprise Linux 5 (RHEL5), which can be exploited by attackers to obtain root privileges. Of particular interest is the fact that the exploit is even able to circumvent security extensions such as SELinux.

A security researcher has released zero-day code for a flaw in the Linux kernel, saying that it bypasses security protections in the operating system. The source code for the exploit was made available last week by researcher Brad Spengler on the Dailydave mailing list.

I have been hearing a lot lately about how Windows Vista is supposedly more secure overall than the popular Linux distros in the market today. After soaking this in and having a chance to think about it, I can come to only one conclusion: Microsoft must believe that vulnerabilities are worse than actual, in-motion exploits being used against exiting operating systems.

A software developer has uncovered a bug in most versions of Linux that could allow untrusted users to gain complete control over the open-source operating system. The null pointer dereference flaw was only fixed in the upcoming 2.6.32 release candidate of the Linux kernel, making virtually all production versions in use at the moment vulnerable.

Linux kernel is the central component of Linux operating systems. It is responsible for managing the system's resources, the communication between hardware and software and security. Unfortunately, stock kernel is not secured out of box. There are some important Linux kernel patches to secure your box. They differ significantly.

Historically, there have been some [gnu/linux effecting viruses]. And there are browser exploits, of course, that no operating system is completely immune from. However, viruses, as we think of them in the Windows world, are highly unusual.

Not to defend Microsoft, as kernel exploits that provide privileged access are terrible flaws, but we had an interesting discussion in the talkbacks where several people acted as if Microsoft was the only place that could’ve made such mistakes.

On July 16, Brad Spengler disclosed an easily-exploitable kernel vulnerability based on getting the kernel to dereference a null pointer. This security hole affected a version of the kernel which had not been widely distributed, so it was a problem for relatively few users, but it highlighted a class of problems which was sure to be seen again.

By now, most readers will be familiar with the local kernel exploit recently posted by Brad Spengler. This vulnerability, which affects the 2.6.30 kernel (and a test version of the RHEL5 "2.6.18" kernel), is interesting in a number of ways. This article will look in detail at how the exploit works and the surprising chain of failures which made it possible.