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              AUSCERT External Security Bulletin Redistribution
                             
                       ESB-1999.119 -- RHSA-1999:029-01
                    Denial of service attack in in.telnetd
                               20 August 1999

===========================================================================

Red Hat Software, Inc. has released the following advisory addressing a
denial of service vulnerability in the remote login daemon in.telnetd.

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		   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:
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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
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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:

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