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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
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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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