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Linux Kernel 2.6 Local Root Exploit
aquatix writes "This local root exploit (Debian, Ubuntu) seems to work everywhere I try it, as long as it's a Linux kernel version 2.6.17 to 2.6.24.1. If you don't trust your users (which you shouldn't), better compile a new kernel without vmsplice." Here is millw0rm's proof-of-concept code.
And the next sound you shall hear are millions of nerds rushing into their offices to compile a new kernel on a sunday afternoon... along with the millions of cell phones ringing as the bosses read this...
Karma Whoring for Fun and Profit.
I strongly suspect this code doesn't do what it says on the tin.
Phew, lucky I run MS Windows then !!
I just successfully used this exploit on a Fedora 7 box running 2.6.22.4. A bit out of date, yes, but a great deal of "home users" who are running Fedora, Debian, Ubuntu (especially Ubuntu), etc., either don't know how to compile their own kernel, or don't care enough to try. Not everyone who uses Linux is going to bother compiling a custom kernel in order to fix a problem like this, especially if they don't have the skills of a sysadmin.
Nope, all you need is remote access to a local user account via ssh or something. Many users use weak passwords. Now you won't have to guess the root password.
Yes, I just verified the exploit on Linux 2.6.17.13 (Slackware 11.0) and Linux 2.6.21.5 (Slackware 12.0) and it works as advertised.
This is quite old code and I had to rewrite it to even compile.
Which reminds me, have you done your emerge -abuop6QvvvvVVvVVxz world yet today?
The average home user that's not willing to put in the effort to compile a new kernel is the home user that doesn't have anyone but either themselves, or people with physical access to the machine using it.
If the only people that have accounts on the machine have physical access to it, this exploit is a lot more work than just opening the box...
There are some pretty funny comments in the source code, regrettably, most people won't understand them. Hell, as a Czech, I *am* probably supposed to understand them, if it were not for the obscure north-eastern dialect of Czech that all the rest of our country finds hilarious (and incomprehensible at the same time).
..." [last for four words utterly incomprehensible :)]
:)) makes me think that had drunk quite a bit before he wrote these gems. Pity that I don't have a good dictionary of spicy English. I'm just rolling on the floor and seriously laughing. :) Oh, and the exploit works, which is not that *funny*.
"Dovalim z knajpy a cumim ze Wojta zas nema co robit, kura." == something like "Just returned from the pub and saw that Wojta [a machine? Or a person? Unclear...] has nothing to do." [The last word might be a Czech expletive with a typo...?]
"Gizdi, tutaj mate cosyk na hrani, kym aj totok vykeca." == something like "Here's something for you to play with, boys,
"Stejnak je to stare jak cyp a aj jakesyk rozbite." == "Anyway, it's old as hell and somehow broken anyway"
The style (no way am I able to render *this* in English
Ezekiel 23:20
nobody$
[..]
[+] mmap: 0xb7f29000
[+] root
root# ^D
nobody$
[..]
Exploit gone!
nobody$
[+] mmap: 0xb7f34000
[-] vmsplice
nobody$ no root for me anymore!
By Morten Hustveit:
"a modification of the exploit that finds the address of sys_vmsplice in the
kernel (using
(using mmap of
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=464953#14
You've got to be kidding me right? Like every sysadmin out there is supposed to know about every feature he doesn't use? Most of the time if you compile out something you'll end up breaking something you do want because you don't understand the internal kernel dependencies or what this really means in terms of functionality. Don't forget I now expect you on duty 24/7 to compile new kernels whenever there's a kernel patch available, particularly when you're sick and or vacation and whoever is filling in for you only knows apt-get/yum/whatever. Anyone that spent that much time on managing a Linux server would probably be fired because he'd be less efficient than a Windows server and an MSCE.
Live today, because you never know what tomorrow brings
Upstream patch for the vulnerability tickled by that specific exploit is here
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=712a30e63c8066ed84385b12edbfb804f49cbc44
Red Hat tracking bug (Enterprise Linux 5 is affected, but 4,3, and 2.1 are not)
https://bugzilla.redhat.com/show_bug.cgi?id=432251
Fedora tracking bug
https://bugzilla.redhat.com/show_bug.cgi?id=432229
You know, I haven't built my own kernel since 'make menuconfig' was the most advanced method around.
I got rather tired of picking and choosing what I need, just to get faster boot times.
That, and any time you need (professional) support for a third-party application, the first thing they ask you is wether you are running a stock kernel.
I -want- to be able to tell MySQL and RedHat to fight it out amongst themselves if my database does not live up to expectations.
I have better things to do with my time than to set-up and analyse endless system profiles, straces and stack dumps.
Grow up, get a real job and see what the real world is like.
You'll find that you no longer have the time to check SANS and packetstorm every day, just to see if your system is secure, spend days just to get that library to compile and then see the entire system go out the window, because it cannot be maintained (because you have be re-assigned to another project).
"I was in love with a beautiful blonde once, dear. She drove me to drink. It's the one thing I am indebted to her for."
The poster who said that Ubuntu kernels are not affected was incorrect, at least partially. The exploit code works as advertised on my Ubuntu machines, both of which are running 7.10 with the latest generic kernel image.
Get your own free personal location tracker
Vmsplice is part of the core kernel, it is not a configuration option. It is used all over the place.
Interested in open source engine management for your Subaru?