Bugtraq mailing list archives
Re: Buffer overflow prevention
From: Shaun Clowes <shaun () securereality com au>
Date: Mon, 18 Aug 2003 09:09:45 +1000
On Fri, Aug 15, 2003 at 11:48:14AM -0700, Crispin Cowan wrote:
Shaun Clowes wrote:Perhaps I'm the only one who feels this way, but I believe that the vast majority of the exploitation of systems is being performed by people with no knowledge of how to write an exploit and that the vast majority of exploits are fragile. Doing anything that makes you different from every other installation of Linux/HPUX/Solaris/InsertOSHere will drastically decrease the changes of any point and click exploit working against you. Could a determined (and knowledgable) attacker still get through? Sure. But if we're talking protections that take very little effort to implement, have a minor performance impact and will save your skin some of the time, it's obvious that it's worth deploying them. As long as you're not kidding yourself that you're then totally secure.Exactly: trivial changes will protect you from script kiddies. Non-bypassability is required to protect you from determined attackers. It depends on your threat model: how much will a penetration event cost you? What is it worth to someone to hack you?
Well, you've immediately eliminated 90% or more of the threat, so it's a good start. In any case, if we are talking about the famous determined attacker it's reasonable to assume that they are going to get you no matter what you do and that you need to carefully consider methods of reducing the damage from intrusion (rather than betting on stopping the intrusion all together).
Its kind of reminiscent of that old joke about the two guys running away from the lion. You don't have to beat the lion, just the other person.But if you taste better (you are a bank and he is a basement RH box) then the lion may choose to chase you anyway.
If I'm the bank I'm probably running Solaris, HP-UX, AIX, Irix etc, in which case I don't even have the option of PaX etc. I would deploy any kind of protection technology I could find (including non-executable stack, moved library images etc). There is no such thing as a perfect protection, and most of the protection technologies that have been discussed in this thread are worth considering. It would seem most pragmatic to deploy whatever you can in your environment. I think it's generally accepted that homogenity breeds insecurity, in which case it makes sense to try to be as different from everyone else as possible even if that doesn't make it impossible for someone to break you. Cheers, Shaun
Current thread:
- Re: Buffer overflow prevention, (continued)
- Re: Buffer overflow prevention Jedi/Sector One (Aug 14)
- Re: Buffer overflow prevention Miod Vallat (Aug 14)
- Re: Buffer overflow prevention Peter Busser (Aug 15)
- Re: Buffer overflow prevention stealth (Aug 15)
- Re: Buffer overflow prevention Mark Tinberg (Aug 18)
- Re: Buffer overflow prevention Crispin Cowan (Aug 18)
- Re: Buffer overflow prevention Peter Busser (Aug 18)
- Re: Buffer overflow prevention Jedi/Sector One (Aug 14)
- Re: Buffer overflow prevention Thomas Sjögren (Aug 14)
- Re: Buffer overflow prevention Shaun Clowes (Aug 15)
- Re: Buffer overflow prevention Crispin Cowan (Aug 15)
- Re: Buffer overflow prevention Shaun Clowes (Aug 18)
- Re: Buffer overflow prevention Crispin Cowan (Aug 18)
- Re: Buffer overflow prevention Mark Handley (Aug 18)
- Re: Buffer overflow prevention Crispin Cowan (Aug 18)
- Heterogeneity as a form of obscurity, and its usefulness Bob Rogers (Aug 22)
- Re: Heterogeneity as a form of obscurity, and its usefulness Crispin Cowan (Aug 22)
- Re: Heterogeneity as a form of obscurity, and its usefulness Nicholas Weaver (Aug 22)
- Re: Buffer overflow prevention Patrick Dolan (Aug 14)