Note: This is an archival copy of Security Sun Alert 200410 as previously published on http://sunsolve.sun.com.|
Latest version of this security advisory is available from http://support.oracle.com as Sun Alert 1000295.1.
Solaris 9 Operating System
Solaris 7 Operating System
Solaris 8 Operating System
Date of Workaround Release
Date of Resolved Release
A local or remote unprivileged user may be able to gain unauthorized root privileges or cause a denial of service due to a "double-free" vulnerability in the CDE login service dtlogin(1X) which can be triggered when parsing invalid X Display Manager Control Protocol (XDMCP) packets. If the dtlogin(1X) program is killed, users will be unable to login on any Sun Ray devices attached to the server, and the console will display the command line login prompt.
This issue is also described in CERT Vulnerability VU #179804 (see http://www.kb.cert.org/vuls/id/179804)
This issue can occur in the following releases:
This issue may occur on systems running dtlogin(1X). To determine if dtlogin(1X) is running on a system, use the "ps" command as shown below:
% ps -ef | grep dtlogin
If an application core file is captured for this issue, it will be found in "/core" and will contain a stack trace similar to the following:
core 'core' of 2999: /usr/dt/bin/dtlogin -daemon ff310dd8 XdmcpDisposeARRAY8 (0, 0, fef66fc0, fef6a680, ff080fe4, 0) + 4 ff310e74 XdmcpDisposeARRAYofARRAY8 (ffbffb70, 0, 0, 0, ffbffc44, ff) + 1c 00025528 request_respond (ffbffc44, 20, 6, ffbffbfc, 6, 0) + 464 00024398 ProcessRequestSocket (6, 43c00, 1ac, ffbffc44, 270, 18) + 244 00023f68 WaitForSomething (40, 20, 3f400, 6, 3ec00, 1) + 208 000190e8 main (2, 0, 48618, 48400, ffbffe7c, 48400) + 338 00015b68 _start (0, 0, 0, 0, 0, 0) + 10
If dtlogin(1X) exits unexpectedly, it may be restarted using the following command as root:
# /etc/init.d/dtlogin start
To reduce the possibility of the described issue from occurring, network administrators should block UDP(7P) packets to port 177 across any firewall where XDMCP remote session service is not required.
If no graphical login access is required for local console users, Sun Ray devices, or remote XDMCP sessions, dtlogin(1X) may be disabled completely by running the following command as root:
# /usr/dt/bin/dtconfig -d
and then stop the currently running dtlogin:
# /usr/dt/bin/dtconfig -kill
If XDMCP remote session access to a machine is not required at all, but graphical login access for the console and/or Sun Ray devices is required, dtlogin(1X) can be configured to not listen for XDMCP connections by editing the "/etc/dt/config/Xconfig file" and removing the "#" symbol at the beginning of the following line:
# Dtlogin.requestPort 0
If the "/etc/dt/config/Xconfig" file does not exist, create it by doing the following:
# mkdir -p /etc/dt/config # cp /usr/dt/config/Xconfig /etc/dt/config # /etc/init.d/dtlogin reset
Note: Controlling access via the access control list in the "Xaccess" file is not effective at preventing this issue.
This issue is addressed in the following releases:
This solution has no attachment