Re: Solaris telnet vulnberability - how many on your network?

[Nate Eldredge <nge () cs hmc edu>]

On Sat, 17 Feb 2007, Darren Reed wrote:

> In some mail from greimer () fccc edu, sie said:
> > 1) This seems like a case of "old code" somehow creeping back in to the
> > current versions, and that's a phenomenon I've seen happen at a couple of
> > different places that I've worked at over the years. It's kind of a
> > special case of version control gone bad, and I'm interested in how that
> > can happen and how to watch out for it.
> >
> > 1a) People have said that this bug was in old versions of SunOS/Solaris
> > (and AIX I think) but nobody ever nailed down exactly when this was fixed,
> > versionwise. In fact, did anybody reproduce this in anything other than
> > Solaris 10? It'd be nice to know the last old version that has the bug, &
> > the 1st that doesn't.
>
> Solaris's /bin/login has never supported the "-f" command line option
> until Solaris 10 (RTFM) so this exploit was just plain not possible.

That is not correct.  On a Solaris 8 box the -f option is accepted without 
error.   I don't have root so I can't verify that it does the right thing, 
but at least as a normal user "login -f asdfasdf" does nothing while 
"login" without arguments presents a prompt.  So it exists and has some 
effect, notwithstanding the fact the fact that it is not listed in the man 
page.  (RTFM isn't very helpful when it comes to undocumented features! 
:-)

$ uname -a
SunOS mybox 5.8 Generic_117350-44 sun4u sparc SUNW,Ultra-2
$ login
login: ^C
$ login -f asdfasdf
$ man login

NAME
     login - sign on to the system

SYNOPSIS
     login [ -p ]  [ -d device ]  [ -h hostname | [ terminal ]  |
     -r hostname ]  [   name  [ environ ]  ...  ]

> The other avenue for passing command line args to telnet is through
> the TERM telnet option, but Solaris stopped passing that through on
> the command line a long time ago (maybe 2.3 or earlier?)
>
> > 2) Does this have anything to do with the OpenSolaris effort?
>
> No.

In fact, you can look in the OpenSolaris repository and see that the 
initial import of usr/src/cmd/cmd-inet/usr.sbin/in.telnetd.c already 
contained this bug.

> > Like are people pulling in code from other sources?
>
> More people should go back and read Casper's email where he explained
> that it came about with a Kerberos project.

I presume that refers only to the telnetd bug, and not to login -f.

--
Nate Eldredge
nge () cs hmc edu