Bugtraq mailing list archives
SunOS exploit.
From: blind () SEDATED NET (Trevor Linton)
Date: Sun, 18 May 1997 13:36:00 +0000
On sunos, if you execute a clean bash shell then type, export USER="root"
then USER=$LOGNAME, then execute chsh root or chfn root you can change
the root information.
Why?
Well first off chsh and chfn are +s'ed. This is a bad idea in the first
Place, Second off chsh and chfn use the function getenv("USER") most
programs bother to use this instead of geteuid(); getenv("USER") reports
that the user is root (while geteuid(); would report the real userid) and
then since chsh and or chfn is +s'ed it'll change root's shell user
information or ANYONE on the system's information!
On the SunOS system i have i've been able to lock out ANYONES shell
using this exploit and locking out root's shell as well as changing
anyones NAME info in /etc/passwd etc.. etc.. any program that uses
getenv("USER") is vunerable (that's in bash). tcsh and some other
shells i remember don't allow USER and LOGNAME modifying. :\
Anyways here's a rough patch:
1) -s the programs that use getenv(); such as chsh and chfn
2) remove getenv() and replace it with geteuid();
3) possibly get the programmers of bash to fix it so USER and
LOGNAME can't be modified unless it's super-user.
I'm sure theres a way to get root from this exploit butta.. :) oh well.
Trevor Linton (blind) - blind () sedated net support () hax0r org
Swingin' Utters. a juvenile product of the working class.
"People who are having trouble communicating should just shuttup"
Current thread:
- Irix and WWW Yuri Volobuev (May 16)
- SunOS exploit. Trevor Linton (May 18)
- Re: SunOS exploit. Christopher X. Candreva (May 19)
- Re: SunOS exploit. Austin Schutz (May 19)
- Re: SunOS exploit. Daniel Reish (May 20)
- Re: SunOS exploit. Christopher X. Candreva (May 19)
- Re: Irix and WWW James Bonfield (May 19)
- Re: Irix and WWW Bill Paul (May 19)
- SunOS exploit. Trevor Linton (May 18)
