full-disclosure - Re: Buffer overflow prevention

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From: dotslash at snosoft.com (KF)
Subject: Re: Buffer overflow prevention

Hrmm why does this bring HP to mind... oh yeah I remember...

HP-> "... oh you say you found a bunch of overflows... that does not 
matter... there is no way you will bypass our non-executable stack.. we 
are not going to fix any of them... we are gonna let em fester... our 
non-exec stack is Hack proof"

(time elapse... 2 months)

SNO-> "...oh yeah we bypassed your non-exec stack and have successfully 
exploited several of those overflows we told you about a few months ago...
bash-2.05a$ id
uid=201(dotslash) gid=15(users) groups=0(system)
bash-2.05a$ ./TRU64_su
# id
uid=0(root) gid=15(users) groups=15(users),0(system)
# sysconfig -q proc executable_stack
proc:
executable_stack = 0
(hrmm your stack REALLY helped out)

HP-> "ok thanks we will procede to sue you now"

-KF

> 
> It's been proved many times that non-executable stack adds NO security at
> all.
> Every single class of vulnerabilities exploitable with executable stack
> can be also exploited with non-executable stack.
> See for example our article (http://www.phrack.org/show.php?p=56&a=5)
> which shows how to bypass a stack protector even with a non-executable
> stack.
> 
> What we're discussing here is an internal structures and data protecting.
> IMHO the ProPolice (http://www.research.ibm.com/trl/projects/security/ssp/),
> is the best protection in this kind, even comparing to "two stack"
> approach.
> Beside that it's an existing, well tested and wide used (for example
> OpenBSD uses it by default now).
> I see no real reason why the major Linux companies are not using it for
> its products.
> 
> Best regards,
> 
> --
> Mariusz Woloszyn
> Internet Security Specialist, GTS - Internet Partners
> _______________________________________________
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