Operating System:

Published:

09 April 2004

Protect yourself against future threats.

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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                ESB-2004.0263 -- Sun(sm) Alert Notification
               sshd May Fail to Log SSH Client IP Addresses
                               09 April 2004

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                sshd
Publisher:              Sun Microsystems
Operating System:       Solaris 9
Platform:               SPARC
                        IA-32
Impact:                 Reduced Security
Access Required:        Remote

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   DOCUMENT ID: 57538
   SYNOPSIS: The Sun Secure Shell Daemon (sshd(1M)) May Fail to Log SSH
   Client IP Addresses
   DETAIL DESCRIPTION:
   
Sun(sm) Alert Notification

     * Sun Alert ID: 57538
     * Synopsis: The Sun Secure Shell Daemon (sshd(1M)) May Fail to Log
       SSH Client IP Addresses
     * Category: Security
     * Product: Solaris
     * BugIDs: 4725702
     * Avoidance: Patch, Workaround
     * State: Resolved
     * Date Released: 07-Apr-2004
     * Date Closed: 07-Apr-2004
     * Date Modified:
       
1. Impact

   The Sun Secure Shell Daemon (sshd(1M)) may fail to log the IP address
   of client systems which connect to the sshd(1M) daemon with the ssh(1)
   client utility. The IP address logged will contain all zeros rather
   than the correct IP address.
   
2. Contributing Factors

   This issue can occur in the following releases:
   
   SPARC Platform
     * Solaris 9 without patch 113273-05
       
   x86 Platform
     * Solaris 9 without patch 114858-04
       
   Note: Solaris 7 and 8 do not ship the Sun Secure Shell Daemon
   (sshd(1M)) and are therefore not impacted by this issue.
   
   A system is only affected by this issue if the sshd configuration file
   (sshd_config(4)) has the "ListenAddress" keyword configured as
   "0.0.0.0" which means to listen on only IPv4 (see inet(3SOCKET))
   configured interfaces. For example:
    $ grep ListenAddress /etc/ssh/sshd_config
    ListenAddress 0.0.0.0                  

   To determine which interfaces on a system are configured to use IPv4
   the following command can be run:
    $ ifconfig -a4
    lo0: flags=1000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4> mtu 8232 index 1
           inet 127.0.0.1 netmask ff000000 
    eri0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1400 index 2
           inet 192.168.254.202 netmask ffffff00 broadcast 192.168.254.255     
                              

3. Symptoms

   The Sun Secure Shell Daemon (sshd(1M)) by default writes to the system
   log (syslog(3C)) with a default severity level of "info" and a
   facility of "auth". If system messages of type "auth.info" or "*.info"
   are configured to be logged in the syslog.conf(4) file, the messages
   from sshd with an IP address of all zeros will look similar to:
    $ grep sshd $(awk '/(auth.info|\*.info)/ {print $NF}' /etc/syslog.conf)
    Apr  2 16:38:16 sunhost sshd[124383]: [ID 800047 auth.info] Accepted
    password for username from 0.0.0.0 port 53979 ssh2                  

   SOLUTION SUMMARY:
   
4. Relief/Workaround

   For sites which are utilizing both IPv4 and IPv6 (see inet(3SOCKET))
   network interfaces, to prevent this issue from occurring the
   sshd_config(4) file can be edited to listen on both IPv4 and IPv6
   configured interfaces by setting the "ListenAddress" keyword to
   contain two colons (::). For example:
    $ grep ^ListenAddress /etc/ssh/sshd_config
    ListenAddress ::                  

   If the sshd_config(4) file is modified, the sshd daemon needs to be
   sent a SIGHUP signal to re-read the file. For example, as the root
   user:
    # pkill -HUP sshd                  

5. Resolution

   This issue is addressed in the following releases:
   
   SPARC Platform
     * Solaris 9 with patch 113273-05 or later
       
   x86 Platform
     * Solaris 9 with patch 114858-04 or later
       
   This Sun Alert notification is being provided to you on an "AS IS"
   basis. This Sun Alert notification may contain information provided by
   third parties. The issues described in this Sun Alert notification may
   or may not impact your system(s). Sun makes no representations,
   warranties, or guarantees as to the information contained herein. ANY
   AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
   WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
   NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT
   YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT,
   INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE
   OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN.
   This Sun Alert notification contains Sun proprietary and confidential
   information. It is being provided to you pursuant to the provisions of
   your agreement to purchase services from Sun, or, if you do not have
   such an agreement, the Sun.com Terms of Use. This Sun Alert
   notification may only be used for the purposes contemplated by these
   agreements.
   
   Copyright 2000-2004 Sun Microsystems, Inc., 4150 Network Circle, Santa
   Clara, CA 95054 U.S.A. All rights reserved.

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