Latest revision as of 18:26, 10 February 2012

[edit] Processes inside a chroot are able to invoke fchdir

This vulnerability means that certain types of attacks on the kernel are possible that can lead to a complete compromise of the system. "chroots" are ways of limiting access to the system, they are like a file system "jail". A process can be restricted to a certain part of the filesystem, and can not access or see anything else.

Users and processes can be placed into a chroot, which would prevent them from seeing and accessing other parts of the system. A well-known method of breaking chroots is by using the fchdir function. This can be used to "fchdr" to a file descriptor of the chrooting process that points to a directory outside the filesystem.

The ASL kernel contains security measures to prevent this.

If you see this vulnerability it can only be caused if you are not running the ASL kernel.

[edit] Next Steps

Check to see if you are using the ASL kernel by going to this link.

If you are not running the ASL kernel:

Please check that you have the kernel installed and then reboot your system into the ASL kernel.

Note: If you have a VPS system, you will not have your own kernel. Please install ASL on the host server.