Vulnerability Note VU#327281

Solaris rpc.yppasswdd does not adequately check input allowing users to execute arbitrary code

Overview

A remotely exploitable buffer overflow exists in the 'rpc.yppasswd' service on Solaris 2.6, 2.7, and 2.8.

I. Description

Network Information Service (NIS) provides a simple network lookup service consisting of databases and processes. Its purpose is to provide information, that has to be known throughout the network, to all machines on the network. Information likely to be distributed by NIS might be login names and/or group information. A remotely exploitable buffer overflow exists in the 'rpc.yppasswd' service. This vulnerability could allow a remote intruder to execute arbitrary code with superuser privileges on an NIS master server. Note that only NIS master servers running the rpc.ypasswdd process are affected. For more information, please see this Sun Alert.

II. Impact

Remote intruders can execute arbitrary code with super user privileges on a NIS master server.

III. Solution

Contact vendor for patches.

If you cannot immediately patch your systems, the following are suggested workarounds until a patch can be applied:

Stop the rpc.yppasswd process. Note that by stopping this service, all users in the NIS domain will be unable to change their NIS password.
Enable non-executable user program stacks in the kernel by adding the following lines to the NIS servers "/etc/system" file:

set noexec_user_stack = 1
set noexec_user_stack_log = 1

Note that a subsequent reboot is required after this change. Additionally, you must restart the rpc.yppasswd process.
Systems Affected

Vendor Status Date Updated

Sun Microsystems Inc. Vulnerable 4-Oct-2001

References

http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=salert%2F27486&zone_32=yppasswd%2A%20%202748%2A%20
http://www.incidents.org/news/yppassword.php
http://archives.neohapsis.com/archives/bugtraq/2001-05/0273.html

Credit

This document was written by Ian A. Finlay.

Other Information

Date Public	07/05/2001
Date First Published	10/04/2001 04:14:03 PM
Date Last Updated	12/18/2002
CERT Advisory
CVE-ID(s)	CVE-2001-0779
NVD-ID(s)	CVE-2001-0779
US-CERT Technical Alerts
Metric	31.39
Document Revision	41

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