Note: This is an archival copy of Security Sun Alert 201445 as previously published on
Latest version of this security advisory is available from as Sun Alert 1001090.1.
Article ID : 1001090.1
Article Type : Sun Alerts (SURE)
Last reviewed : 2010-01-19
Audience : PUBLIC
Copyright Notice: Copyright © 2010, Oracle Corporation and/or its affiliates.

Sun Linux NIS server ("ypserv") is Vulnerable to a Denial of Service (DoS) Attack


Release Phase

Bug Id

Date of Resolved Release

On Sun Linux 5.0, a local or remote unprivileged user ...

1. Impact

On Sun Linux 5.0, a local or remote unprivileged user may be able to prevent the "ypserv" NIS server process from answering NIS name service requests. As a result, clients currently bound to this NIS server may experience hangs or slowdowns. Users may no longer be able to login on affected NIS clients.

This issue is described in Red Hat Advisory RHSA-2003:173-07, available at:

2. Contributing Factors

This issue can occur in the following releases:

Sun Linux

  • Sun Linux 5.0 (LX50) with ypserv-1.3.12-2

Note: Sun Linux 5.0 is currently shipped with the Sun LX50 Server.

3. Symptoms

Should the described issue occur, the NIS server will not longer respond to client NIS requests. The "ypserv" process will still be present in the "ps -ef" command output.

4. Workaround

To recover from an unresponsive NIS server, restart the "ypserv" process by issuing the following commands as a root user:

    # /etc/init.d/ypserv stop
# /etc/init.d/ypserv start

Until this issue is resolved, sites may consider to disable NIS server functionality on affected Sun Linux systems.

5. Resolution

This issue is addressed in the following releases:

Sun Linux

  • Sun Linux 5.0 (LX50) with ypserv-2.8-0.72E.i386.rpm or later

Sun Linux patches are available at

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Sun Linux 5.0

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