Software Engineering Institute

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.

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

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:

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