A chroot on Red Hat / CentOS / Fedora Linux operating changes the apparent disk root directory for the Apache process and its children. Once this is done attacker or other php / perl / python scripts cannot access or name files outside that directory. This is called a "chroot jail" for Apache. You should never ever run a web server without jail. There should be privilege separation between web server and rest of the system.
news.softpedia.com: Yesterday, November 27th, the Ubuntu developers discovered yet another security issue (actually, more than one) in the Linux kernel packages. These vulnerabilities affect the following Ubuntu distributions: 6.06 LTS, 7.10, 8.04 LTS and 8.10 (also applies to Kubuntu, Edubuntu and Xubuntu).
linuxhaxor.net: There seems to be a false sense of security among some Linux users. The number of malicious programs specifically written for GNU/Linux has been on the increase in recent years and in the year of 2005 alone has more than doubled: from 422 to 863.
blogs.zdnet: A remote buffer overflow vulnerability in the Linux Kernel could be exploited by attackers to execute code or cripple affected systems, according to a Gentoo bug report that just became public.
computerworld.com.au: Looming attacks will soon pop the security bubble enjoyed by Linux and Macintosh users, according to Russian security expert Eugene Kaspersky.
computerworld.com: A popular Firefox add-on designed to block scripts and plug-ins has been updated to stymie the new "clickjacking" class of attacks, the extension's developer said today.
techworld.com (IDG): Internet infrastructure vendors are rushing to develop patches for a set of TCP/IP security flaws, which could help hackers knock servers offline with very little effort. Robert Lee and Jack Louis, have said that they can knock Windows, Linux, embedded systems and even firewalls offline.
cyberciti.biz: Really scary exploit attack in wild, which affects all browsers under any desktop operating systems including MS IE, Linux, Apple safari, Opera, Firefox and Adobe flash. Any website that uses CSS, flash and IFRAME can be used to attack on end users. Attacker is able to take control of the links that your browser visits.
telegraph.co.uk: Hackers have mounted an attack on the Large Hadron Collider, raising concerns about the security of the biggest experiment in the world as it passes an important new milestone.
blog.perens.com: Last month, Red Hat issued a security bulletin. Not all that went on is clear, but it seems that the servers used to develop and distribute Fedora and Red Hat were accessed by a person with criminal intent. But there are continuing problems with Red Hat's handling of the situation.
Also: Fedora and our security attitude