Re: how an hacker can bypass a chrooted environement ?

On Sun, 14 May 2006, Norbert Francois wrote:

Thank you very much for your replies.

But there's smth I still don't understand. Few months ago I tried to install a jail chroot with "jail" (http://www.jmcresearch.com/projects/jail/howto.html). In the chrooted environement I didn't copy programs like "chroot" (itself), "mknod" or "mount" known to be dangerous... So the only way to bypass this chroot is to manually upload these tools ? If it is the case, the attacker has to inject a code opening a socket on the victim's computer, isn't it ?

Obviously, the mentioned chroot(2), mknod(2) and mount(2) aren't programs, but actual syscalls:

$ man 2 chroot
$ man 2 mknod
$ man 2 mount

Unless there are some mechanisms to enforce syscall execution limitation (like systrace or similar) in place, you are able to execute any syscall inside a chroot jail -- provided you have the required privileges, of course.

Take also a look at the differences between regular chroot and FreeBSD's jail, it might be of some interest to you:

http://en.wikipedia.org/wiki/Chroot_jail
http://en.wikipedia.org/wiki/FreeBSD_Jail

Hope this helps to clarify things a bit;)

Cheers,

--
Marco Ivaldi
Antifork Research, Inc. http://0xdeadbeef.info/
3B05 C9C5 A2DE C3D7 4233 0394 EF85 2008 DBFD B707


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