lkml.org 
[lkml]   [2001]   [Oct]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Flaws in recent Linux kernels
When was this fixed in the 2.4 -ac series?  I don't see anything in
notes.249 or notes.2410 about it.

(see http://lists.insecure.org/bugtraq/2001/Oct/0140.html for
the entire advisory)

On Thu, Oct 18, 2001 at 05:35:40PM +0000, Rafal Wojtczuk wrote:
[...]
>
> Hello,
> There are two bugs present in Linux kernels 2.2.x, x<=19 and 2.4.y,
> y<=9. The first vulnerability results in local DoS. The second one,
> involving ptrace, can be used to gain root privileges locally (in case of
> default install of most popular distributions). Linux 2.0.x is not vulnerable
> to the ptrace bug mentioned.
>
[...]
>
> III. Vendor status
> The kernel developers were notified on 18th September.
> vendor-sec at lists dot de was notified on 9th October.
>
> IV. Availability of patches.
> 2.4.12 kernel fixes both presented problems. The attached patches,
> 2.2.19-deep-symlink.patch and 2.2.19-ptrace.patch, both blessed by Linus,
> can be used to close the vulnerability in 2.2.19. The (updated)
> Openwall GNU/*/Linux kernel patches can be retrieved from
> http://www.openwall.com/linux/
> Note that the default Owl installation is not vulnerable to the ptrace bug
> described.
>
> V. The exploits
> The attached mklink.sh script creates malicious symlinks.
> ptrace-exp.c and insert_shellcode.c exploit the ptrace bug on i386
> architecture. You will probably need to adjust #define in the latter. Note
> that ptrace-exp uses LD_DEBUG variable to force a setuid program to generate
> output. This technique (stderr redirected to a pipe, LD_DEBUG set, especially
> LD_DEBUG=symbols) allows for forced suspending of a setuid binary in a
> precisely determined moments, which may be helpful to build exploits which
> rely on race-conditions. And finally, notice that under Owl LD_DEBUG is
> ignored in case of suid binaries.
>
> Save yourself,
> Nergal
> http://www.7bulls.com
>
>

--
"I think a lot of the basis of the open source movement comes from
procrastinating students..."
-- Andrew Tridgell <http://www.linux-mag.com/2001-07/tridgell_04.html>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:08    [W:0.033 / U:5.260 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site