Security Advisory					CERT-NL
Author/Source	:	Xander Jansen	Index	:		S-00-08
Distribution	:	World	Page	:		1
Classification	:	External	Version	:		1
Subject	:	SGI IRIX fam service Vulnerability	Date	:		04-Mar-2000

By courtesy of Silicon Graphics we received information on a vulnerability in the SGI IRIX fam service allowing remote users acces to local information.
CERT-NL recommends to follow the steps outlined below.

SGI Security Advisory

Title:	fam Vulnerability
Title:	NAI-0016: Silicon Graphics IRIX fam service
Number:	20000301-01-I
Date:	March 1, 2000

SGI provides this information freely to the SGI user community for its consideration, interpretation, implementation and use. SGI recommends that this information be acted upon as soon as possible.

SGI provides the information in this Security Advisory on an "AS-IS" basis only, and disclaims all warranties with respect thereto, express, implied or otherwise, including, without limitation, any warranty of merchantability or fitness for a particular purpose. In no event shall SGI be liable for any loss of profits, loss of business, loss of data or for any indirect, special, exemplary, incidental or consequential damages of any kind arising from your use of, failure to use or improper use of any of the instructions or information in this Security Advisory.

As a followup to the NAI Advisory #16: "Silicon Graphics IRIX fam service", SGI has investigated and has open sourced fam which includes the fix to this vulnerability.

The fam daemon is an RPC server that tracks changes to the filesystem.

NAI has reported that a vulnerability has been discovered in fam which allows an attacker to learn the names of files and directories on IRIX systems.

SGI has investigated the issue and recommends the following steps for neutralizing the exposure. It is recommended that these measures be implemented on all vulnerable SGI systems running the fam service.

The fam daemon is installed by default on all versions of IRIX 5.X and IRIX 6.X.

A local user account on the vulnerable system is not required in order to exploit the fam daemon.

The vulnerability can be exploited remotely by using carefully crafted RPC packets that are sent to the fam daemon.

The vulnerability leads to unauthorized access to the names of files and directories on an IRIX system.

This vulnerability was reported by Network Associates, Inc. in Advisory NAI-0016:
http://www.nai.com/nai_labs/asp_set/advisory/16_fam_adv.asp

This vulnerability has been publicly discussed in Usenet newsgroups and mailing lists.

Although a version of fam which fixes this vulnerability is available as open source, it is realized that there may be situations where compiling and installing the new version may not be possible.

The steps below can be used to disable the fam daemon.

 

**** WARNING ****

Disabling fam daemon will impact and/or disable applications that use the RPC-based fam daemon. This includes fm, mailbox, mediad, scanners, sysmon , fxbuilder, IRIS Annotator and applications like MediaMail that linked with the libfam.a static library.

1. Become the root user on the system.

   % /bin/su -
   Password:
   #

2. Comment out the fam service in /etc/inetd.conf

   # vi /etc/ined.conf

   Change the line:

   sgi_fam/1 stream rpc/tcp wait root ?/usr/etc/fam fam

   To:

   #sgi_fam/1 stream rpc/tcp wait root ?/usr/etc/fam fam

   and save the file.

3. Restart inetd..

   # /etc/killall -HUP inetd

4. Kill any running fam daemon
   NOTE: This may disable applications that use fam including MediaMail.

   # /etc/killall fam

5. Return to previous level.

   # exit
   %

Solution

SGI has open sourced the fam daemon and the source code is available from:
http://oss.sgi.com/projects/fam/

The open source version of fam has a fix for this vulnerability.

Patches are being built for currently supported IRIX operating systems and this advisory will be updated when these patches are made available.

The fam vulnerability is scheduled to be fixed in IRIX 6.5.8

Acknowledgments

SGI wishes to thank the Network Associates, Inc. for their assistance in this matter.

SGI Security Information/Contacts

If there are questions about this document, email can be sent to cse-security-alert@sgi.com.

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