Vulnerability Development mailing list archives
Re: Core Dump as an Intrusion Event
From: "Eclipse, Solar" <solareclipse () PHREEDOM ORG>
Date: Thu, 5 Oct 2000 11:22:57 -0500
On Thu, Oct 05, 2000 at 07:00:15AM -0700, Crispin Cowan wrote:
Background: StackGuard 2.0 (as released this summer) does not provide secure resistance to format bugs. However, because StackGuard changes some data layouts, it does tend to change the offsets that are required to make the exploit work. As a result, exploits tuned for the "standard" instance of a vulnerable program tend to just cause the victim program to dump core without giving up the shell prompt. This leads me to conjecture that "core dump" makes a good intrusion detection event. Server apps. ("services", e.g. Apache, ftpd, fingerd ;-) should not be dumping core, so you could treat a core dump as an indication that an attacker is rattling your door. StackGuard enhances this effect, by making it unlikely that the first attack attempt will work. Other factors may also be used to enhance this effect. In theory, theory is just like practice, but in practice it's different. Anyone have practical comments on this hypothesis? In practice, how often do services dump core for non-security reasons? If services dump core for non-security reasons even just a little, then the false-positive rate of intrusion detection from this clue gets out of control.
This is a very interesting idea and it needs further research. System services on Linux dump core very rarely and a core dump can indeed be an indication that something is wrong. Keep in mind that core dumps can be disabled and that it's easy to delete any evidence once the attacker has root access. A better solution would be a kernel patch that hooks into the SIGSEGV signal handler and logs all segmentation faults. A predefined list of programs can be monitored. Maybe it's fesable to log segfaults of all root processes. Maybe the kernel module could take further action to stop the attacker, but I don't know exactly how this could be accomplished. Solar Eclipse <solareclipse () phreedom org> Phreedom Magazine http://www.phreedom.org
Current thread:
- Core Dump as an Intrusion Event Crispin Cowan (Oct 05)
- Re: Core Dump as an Intrusion Event Alexander Kiwerski (Oct 05)
- Re: Core Dump as an Intrusion Event antirez (Oct 05)
- Re: Core Dump as an Intrusion Event Slawek (Oct 05)
- Re: Core Dump as an Intrusion Event Pascal Bouchareine (Oct 05)
- Re: Core Dump as an Intrusion Event Crist Clark (Oct 05)
- Re: Core Dump as an Intrusion Event W. Reilly Cooley (Oct 05)
- Re: Core Dump as an Intrusion Event Eclipse, Solar (Oct 05)
- Re: Core Dump as an Intrusion Event Erik Tayler (Oct 06)
- Re: Core Dump as an Intrusion Event Jarno Huuskonen (Oct 06)
- Re: Core Dump as an Intrusion Event Crist Clark (Oct 07)
- Re: Core Dump as an Intrusion Event Kev (Oct 07)
- Re: Core Dump as an Intrusion Event antirez (Oct 08)
- Re: Core Dump as an Intrusion Event Jarno Huuskonen (Oct 08)
- Re: Core Dump as an Intrusion Event Gigi Sullivan (Oct 09)
- Re: Core Dump as an Intrusion Event Jarno Huuskonen (Oct 09)
- Re: Core Dump as an Intrusion Event Gigi Sullivan (Oct 11)
- Re: Core Dump as an Intrusion Event antirez (Oct 12)