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[linux-security] Re: [RHSA-1999:029-01] Denial of service attack in in.telnetd



Is redhat 5.1 immune to the attack?  Or is it no longer supported for
patches?  It seems strange that both 4.2 and 5.2 are vulnerable, but
neither 5.0 nor 5.1 are, so I'm wondering.

Redhat makes new OS releases so frequently that we've had to start
skipping every other OS release to keep our patch labor down - so we've
been doing 4.2, 5.1, 6.0...  and projecting 6.2, 7.1, 8.0...  So if
redhat decides not to do the extensive patch releases needed to make
their frequent OS releases relatively liveable, we're pretty much
screwed; we have a lot of 5.1 machines that'll need patches in the
future, and finishing up y2k on our other platforms (sun, sgi, dec) is
going to have to take priority over upgrading redhat 5.1 machines.

Basically, we have a lot of clients.  If we can persuade each of them
individually to upgrade once every two years (about four redhat
releases!), we're lucky - often things get strung out for three years
(about 6 redhat releases!), and the really cantankerous users may hold
on longer than that (yikes).  This new release every six months stuff is
hurting us enough already (because we have to say "sorry, we aren't
supporting the latest release right now" sometimes); if redhat stops
releasing patches soon after a given OS release is made, we'll be in for
a lot of pain.

Please, tell me I'm wrong about this, that it just happened that 5.0 and
5.1 weren't vulnerable.

Bill Nottingham wrote:
> 
> ---------------------------------------------------------------------
>                    Red Hat, Inc. Security Advisory
> 
> Synopsis:               Denial of service attack in in.telnetd
> Advisory ID:            RHSA-1999:029-01
> Issue date:             1999-08-19
> Updated on:
> Keywords:               telnet telnetd
> Cross references:
> ---------------------------------------------------------------------
> 
> 1. Topic:
> 
> A denial of service attack has been fixed in in.telnetd.
> 
> 2. Bug IDs fixed (http://developer.redhat.com/bugzilla/):
> 
> 4560
> 
> 3. Relevant releases/architectures:
> 
> Red Hat Linux 4.2, 5.2, 6.0, all architectures
> 
> 4. Obsoleted by:
> 
> 5. Conflicts with:
> 
> 6. RPMs required:
> 
> Red Hat Linux 4.2:
> 
> Intel:
>   ftp://ftp.redhat.com/redhat/updates/4.2/i386/NetKit-B-0.09-11.i386.rpm
> 
> Alpha:
>   ftp://ftp.redhat.com/redhat/updates/4.2/alpha/NetKit-B-0.09-11.alpha.rpm
> 
> Sparc:
>   ftp://ftp.redhat.com/redhat/updates/4.2/sparc/NetKit-B-0.09-11.sparc.rpm
> 
> Source packages:
>   ftp://ftp.redhat.com/redhat/updates/4.2/SRPMS/NetKit-B-0.09-11.src.rpm
> 
> Red Hat Linux 5.2:
> 
> Intel:
>   ftp://ftp.redhat.com/redhat/updates/5.2/i386/telnet-0.10-28.5.2.i386.rpm
> 
> Alpha:
>   ftp://ftp.redhat.com/redhat/updates/5.2/alpha/telnet-0.10-28.5.2.alpha.rpm
> 
> Sparc:
>   ftp://ftp.redhat.com/redhat/updates/5.2/sparc/telnet-0.10-28.5.2.sparc.rpm
> 
> Source packages:
>   ftp://ftp.redhat.com/redhat/updates/5.2/SRPMS/telnet-0.10-28.5.2.src.rpm
> 
> Red Hat Linux 6.0:
> 
> Intel:
>   ftp://ftp.redhat.com/redhat/updates/6.0/i386/telnet-0.10-29.i386.rpm
> 
> Alpha:
>   ftp://ftp.redhat.com/redhat/updates/6.0/alpha/telnet-0.10-29.alpha.rpm
> 
> Sparc:
>   ftp://ftp.redhat.com/redhat/updates/6.0/sparc/telnet-0.10-29.sparc.rpm
> 
> Source packages:
>   ftp://ftp.redhat.com/redhat/updates/6.0/SRPMS/telnet-0.10-29.src.rpm
> 
> 7. Problem description:
> 
> in.telnetd attempts to negotiate a compatible terminal type
> between the local and remote host. By setting the TERM
> environment variable before connecting, a remote user could
> cause the system telnetd to open files it should not. Depending
> on the TERM setting used, this could lead to denial of service
> attacks.
> 
> Thanks go to Michal Zalewski and the Linux Security Audit team
> for noting this vulnerability.
> 
> 8. Solution:
> 
> For each RPM for your particular architecture, run:
> 
> rpm -Uvh <filename>
> 
> where filename is the name of the RPM.
> 
> 9. Verification:
> 
> MD5 sum                           Package Name
> --------------------------------------------------------------------------
> 0c425c34fb77a8309ff10b4143e9b847  i386/NetKit-B-0.09-11.i386.rpm
> d791d645adeb5fa0147c1058b21cbbac  alpha/NetKit-B-0.09-11.alpha.rpm
> bfbd440845191bbdcf8be21ee59bf6a8  sparc/NetKit-B-0.09-11.sparc.rpm
> ccd5ab53c423e468d66ca801c90b5ae4  SRPMS/NetKit-B-0.09-11.src.rpm
> 
> ef33f3c5ca810d05420e57b5cfcf8928  i386/telnet-0.10-28.5.2.i386.rpm
> 6dc23437a200193b0bfed23d5f5e6562  alpha/telnet-0.10-28.5.2.alpha.rpm
> 49c38457cc0a82a680fd9b9634dc8021  sparc/telnet-0.10-28.5.2.sparc.rpm
> 2f33670a683e3abef0e4914586c71961  SRPMS/telnet-0.10-28.5.2.src.rpm
> 
> 4360d47490f13d60b8737d28dc88825a  i386/telnet-0.10-29.i386.rpm
> 90213fcdca41a3ed12ab7d92344e7286  alpha/telnet-0.10-29.alpha.rpm
> 277787dbc39dff8ea84d4b16dcb7a954  sparc/telnet-0.10-29.sparc.rpm
> 269783a0754d234f7bef0f4717a8dbc2  SRPMS/telnet-0.10-29.src.rpm
> 
> These packages are PGP signed by Red Hat Inc. for security.  Our key
> is available at:
> 
> http://www.redhat.com/corp/contact.html
> 
> You can verify each package with the following command:
> 
> rpm --checksig  <filename>
> 
> If you only wish to verify that each package has not been corrupted or
> tampered with, examine only the md5sum with the following command:
> 
> rpm --checksig --nopgp <filename>
> 
> 10. References:
> 
> --
> ----------------------------------------------------------------------
> Please refer to the information about this list as well as general
> information about Linux security at http://www.aoy.com/Linux/Security.
> ----------------------------------------------------------------------
> 
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>   mail -s unsubscribe linux-security-request redhat com < /dev/null



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