Updated ypserv packages fix various vulnerabilities

Updated ypserv packages which fix a denial of service (DoS) vulnerability
and a memory leak are now available for Red Hat Linux on IBM iSeries and
pSeries systems.

The ypserv package contains the Network Information Service (NIS) server.

For ypserv versions before 2.5 it was discovered that a memory leak which
can be triggered remotely. When someone requests a map that does not exist,
a previous mapname may be returned. This happens, for instance, if the
command "ypmatch foo aaaaaaaaaaaaaaaaaaaa" is run. Repeatedly running this
command will result in the NIS server using more memory and running more
slowly. This condition can lead to the killing of the ypserv process due to
the system being out of memory. The Common Vulnerabilities and Exposures
project (cve.mitre.org) has assigned the name CAN-2002-1232 to this issue.

For ypserv version 2.7 and before, a malicious client can block NIS
requests. To do this, the malicious client queries ypserv via TCP and then
ignores the server's response. The ypserv daemon will then wait
indefinitely for a response from the client indicating it received the
message. During this time no other client requests are answered by ypserv,
causing a DoS. Versions 2.7 and greater of ypserv have been altered to fork
a child process for each client request -- thus preventing any one request
from causing a DoS. The Common Vulnerabilities and Exposures project
(cve.mitre.org) has assigned the name CAN-2003-0251 to this issue.

Red Hat recommends that users of NIS immediately upgrade to the packages
contained within this erratum, which are not vulnerable to these

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

To update all RPMs for your particular architecture, run:

rpm -Fvh [filenames]

where [filenames] is a list of the RPMs you wish to upgrade. Only those
RPMs which are currently installed will be updated. Those RPMs which are
not installed but included in the list will not be updated. Note that you
can also use wildcards (*.rpm) if your current directory *only* contains the
desired RPMs.

Please note that this update is also available via Red Hat Network. Many
people find this an easier way to apply updates. To use Red Hat Network,
launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate
RPMs being upgraded on your system.

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2002-1232
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2003-0251
http://www.linux-nis.org/nis/ypserv/ChangeLog

DoS, NIS, ypserver