Date: 21 Mar 2002 03:47:13 -0000
From: Mandrake Linux Security Team <[email protected]>
To: [email protected]Subject: MDKSA-2002:025 - fix for insecure default kdm configuration
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________________________________________________________________________
Mandrake Linux Security Update Advisory
________________________________________________________________________
Package name: kdm
Advisory ID: MDKSA-2002:025
Date: March 20th, 2002
Affected versions: 7.1, 7.2, 8.0, Corporate Server 1.0.1
________________________________________________________________________
Problem Description:
A problem was discovered with the default configuration of the kdm
display manager in Mandrake Linux. By default, it allows XDMCP
connections from any host, which can be used to obtain a login screen
on your system remotely. This can be used to get a list of users on
that host, as displayed by kdm. It can also be used to circumvent
access control mechanisms such as tcpwrappers and root login
restrictions on the console and via remote.
Solution:
To disable remote connections, edit the /etc/X11/xdm/Xaccess file and
change the following two lines:
* #any host can get a login window
* CHOOSER BROADCAST #any indirect host can get a chooser
to:
#* #any host can get a login window
#* CHOOSER BROADCAST #any indirect host can get a chooser
Please note that Mandrake Linux 8.1 and 8.2 are not vulnerable to this
as newer versions of kdm have a configuration option in the
/usr/share/config/kdm/kdmrc file which explicitly have XDMCP support
disabled.
Also please note that this is only valid if you are running kdm.
________________________________________________________________________
References:
http://www.procheckup.com/security_info/vuln_pr0208.htmlhttp://www.kb.cert.org/vuls/id/634847
________________________________________________________________________
Updated Packages:
There are no updated packages available. Please refer to the Solution
noted above for the fix.
________________________________________________________________________
Bug IDs fixed (see https://qa.mandrakesoft.com for more information):
________________________________________________________________________
To upgrade automatically, use MandrakeUpdate. The verification of md5
checksums and GPG signatures is performed automatically for you.
If you want to upgrade manually, download the updated package from one
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Please verify the update prior to upgrading to ensure the integrity of
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rpm --checksig <filename>
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Please be aware that sometimes it takes the mirrors a few hours to
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You can view other update advisories for Mandrake Linux at:
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MandrakeSoft has several security-related mailing list services that
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visiting:
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If you want to report vulnerabilities, please contact
[email protected]
________________________________________________________________________
Type Bits/KeyID Date User ID
pub 1024D/22458A98 2000-07-10 Linux Mandrake Security Team
<[email protected]>
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