Security Vulnerability in the DNS Protocol May Lead to DNS Cache Poisoning

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Security Vulnerability in the DNS Protocol May Lead to DNS Cache Poisoning

1. Impact

A security vulnerability in the DNS protocol may allow remote unprivileged users to cause named(1M) to return incorrect addresses for Internet hosts, thereby redirecting end users to unintended hosts or services.

This issue is also referenced in the following documents:


2. Contributing Factors

This issue can occur in the following releases:

SPARC Platform

• Solaris 8 without patch 109326-23
• Solaris 9 without patch 112837-15
• Solaris 10 without patch 119783-06
• OpenSolaris based upon builds snv_01 through snv_94

x86 Platform

• Solaris 8 without patch 109327-23
• Solaris 9 without patch 114265-14
• Solaris 10 without patch 119784-06
• OpenSolaris based upon builds snv_01 through snv_94

Note: Solaris 8 entered EOSL Phase 2 on 1 April 2009. Entitlement to patches developed on or after 1 April 2009 requires the purchase of the Solaris 8 Vintage Patch Service. See Note in section 5 for more details.

OpenSolaris distributions may include additional bug fixes above and beyond the base build from which it was derived. The base build can be derived as follows:

$ uname -a
SunOS  phys-node-1 5.11 snv_94 i86pc i386 i86pc

Only systems with the BIND named(1M) service enabled are impacted by this issue. To verify if BIND is running on a system, the following command can be used:

$ ps -e | grep in.named && echo "BIND is running"

3. Symptoms

There are no predictable symptoms that would indicate the described issue has occurred.

4. Workaround

Please refer to section III, "Solution", of CERT VU#800113, in particular the following headings: "Restrict access", "Filter traffic at network perimeters" and Disable recursion:

http://www.kb.cert.org/vuls/id/800113"

5. Resolution

This issue is addressed in the following releases:

SPARC Platform

• Solaris 8 with patch 109326-23 or later
  
• Solaris 9 with patch 112837-15 or later
• Solaris 10 with patch 119783-06 or later
• OpenSolaris based upon builds snv_95 or later
  

x86 Platform

• Solaris 8 with patch 109327-23 or later
• Solaris 9 with patch 114265-14 or later
  
• Solaris 10 with patch 119784-06 or later
• OpenSolaris based upon builds snv_95 or later

Note 1: The READMEs of Solaris 8 patches developed on or after 1 April 2009 are available to all customers however Solaris 8 entered EOSL Phase 2 on April 1, 2009 and thus entitlement for these patches, including those that fix security vulnerabilities, requires the purchase of the Solaris 8 Vintage Patch Service. More information about the Solaris 8 Vintage Patch Service is available at:

http://www.sun.com/service/eosl/Solaris8.html

Note 2: The above patches implement mitigation strategies within the implementation of the DNS protocol, specifically source port randomization and query ID randomization making BIND 9 more resilient to an attack. It does not, however, completely remove the possibility of exploitation of this issue.

The full resolution is for DNS Security Extensions (DNSSEC) to be implemented Internet-wide. DNS zone administrators should start signing their zones.

If your site's parent DNS zone is not signed you can register with the ISC's DNSSEC Look-aside Validation (DLV) registry at the following URL:

https://secure.isc.org/ops/dlv/

Further details on configuring your DNA zones for DNSSEC is available from the ISC at the following URL:

https://www.isc.org/files/DNSSEC_in_6_minutes.pdf

Note 3: BIND as provided with Solaris 8 is not DNSSEC capable and thus Sun recommends updating Solaris 8 systems acting as DNS servers to Solaris 10 or later.

Note 4: After installation of the above mentioned patches the named(1M) configuration file, by default /etc/named.conf, MUST not have the "query-source" or "query-source-v6" option configured. These options instruct the name server to use only the port configured for outbound queries which means the source port will not be randomized. When disabling these options note that some firewall configuration may be necessary to allow the name server to work though the firewall.

For more information on Security Sun Alerts, see Technical Instruction ID 213557.

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 2000-2009 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, CA 95054 U.S.A. All rights reserved.

Modification History

15-Jul-2008: Updated Workaround and Resolution sections
17-Jul-2008: Updated Workaround section
30-Jul-2008: Updated Workaround section for IDRs release (as published in Sun Alert 240048)
08-Aug-2008: Updated Contributing Factors and Resolution sections; now Resolved
21-Aug-2009: Updated Resolution section for URL broken link

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