Red Hat Bugzilla – Full Text Bug Listing
|Summary:||CVE-2007-0956 Unauthorized access via krb5-telnet daemon|
|Product:||Red Hat Enterprise Linux 4||Reporter:||Marcel Holtmann <holtmann>|
|Component:||krb5||Assignee:||Nalin Dahyabhai <nalin>|
|Status:||CLOSED ERRATA||QA Contact:||Brian Brock <bbrock>|
|Version:||4.0||CC:||jplans, nmiell, security-response-team|
|Fixed In Version:||RHSA-2007-0095||Doc Type:||Bug Fix|
|Doc Text:||Story Points:||---|
|Last Closed:||2007-04-03 14:21:32 EDT||Type:||---|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
Description Marcel Holtmann 2007-02-23 09:36:08 EST
The MIT krb5 telnet daemon (telnetd) allows unauthorized login as an arbitrary user, when presented with a specially crafted username. This is a vulnerability in an application program; it is not a bug in the MIT krb5 libraries or in the Kerberos protocol. A user can gain unauthorized access to any account (including root) on a host running telnetd. Whether the attacker needs to authenticate depends on the configuration of telnetd on that host. The telnetd in all releases of MIT krb5, up to and including krb5-1.6 are affected.
Comment 1 Mark J. Cox 2007-02-23 09:59:46 EST
Note that by default we do not enable telnetd in RHEL and the firewall in RHEL defaults to blocking external access to telnet. A server would be vulnerable to this flaw only if they enable krb5 telnetd using "chkconfig krb5-telnet on" and set the firewall to allow incoming connections to the telnet port.
Comment 4 Mark J. Cox 2007-03-06 03:52:44 EST
Embargo moved by MIT to 20070403
Comment 8 Mark J. Cox 2007-03-27 06:20:21 EDT
Note that this issue is similar to the telnetd flaw found in Solaris: http://www.kb.cert.org/vuls/id/881872 However the technicalities of the flaw are different, and exploitation is different. Therefore the exploits for the Solaris telnetd flaw, and the worm that exploits the Solaris issue do not successfully exploit this issue. Whilst we are not aware of this issue currently being exploited we have confirmed that an exploit is possible and is fairly easy to create.
Comment 10 Mark J. Cox 2007-04-03 14:08:30 EDT
Now public, removing embargo
Comment 11 Red Hat Bugzilla 2007-04-03 14:21:32 EDT
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2007-0095.html