Bugtraq mailing list archives
Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability
From: Dan Yefimov <dan () ns15 lightwave net ru>
Date: Thu, 16 Aug 2007 02:16:53 +0400 (MSD)
On Wed, 15 Aug 2007, Wojciech Purczynski wrote:
Sending a signal to privileged process is a privilege itself.
Sure. But once control was transferred to some other code that we have no control over, we have no more control over when the signal is sent. We just can't send that signal at arbitrary moment. If you as an attacker can create arbitrary setuid root binary in the system, this game is not worth anymore, since you already won.
Under some circumstances this may lead to other consequences. For example I was able to code local root exploit using some very common suid binary, although its usage is somewhat limited.
Again, if an attacker can create arbitrary setuid root binary in the system, the latter is already broken. And if the setuid root binary allows arbitrary code execution on getting some signal, it is vulnerable itself. Unexpected signals can be generated at any time by terminals, init, various system daemons, non-blocking i/o for files open before exec(), alarms, failed pageins, etc. If the program (not necessarily setuid/setgid) can't properly handle those situations, it is broken by design. Signals are not something we can trust. -- Sincerely Your, Dan.
Current thread:
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability, (continued)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Dan Yefimov (Aug 20)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Nicolas Rachinsky (Aug 17)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Dan Yefimov (Aug 17)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Wojciech Purczynski (Aug 14)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Dan Yefimov (Aug 15)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Wojciech Purczynski (Aug 15)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Dan Yefimov (Aug 15)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Wojciech Purczynski (Aug 15)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Dan Yefimov (Aug 15)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Wojciech Purczynski (Aug 16)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Dan Yefimov (Aug 16)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Dan Yefimov (Aug 15)
- Re: COSEINC Linux Advisory #1: Linux Kernel Parent Process Death Signal Vulnerability Wojciech Purczynski (Aug 15)