__________________________________________________________
The U.S. Department of Energy
Computer Incident Advisory Capability
___ __ __ _ ___
/ | /_\ /
\___ __|__ / \ \___
__________________________________________________________
INFORMATION BULLETIN
Multiple Cisco Products Vulnernable to DNS Cache Poisoning Attacks
[Cisco Security Advisory Document ID: 107064]
July 28, 2008 19:00 GMT Number S-341
[REVISED 18 Aug 2008]
______________________________________________________________________________
PROBLEM: Multiple Cisco products are vulnerable to DNS cache poisoning
attacks due to their use of insufficiently randomized DNS
transaction IDs and UDP source ports in the DNS queries that
they produce, which may allow an attacker to more easily forge
DNS answers that can poison DNS caches.
PLATFORM: Cisco IOS Software
Cisco Network Registrar
Cisco Application and Content Networking System
Cisco Global Site Selector Used in Combination with Cisco
Network Registrar
Debian GNU/Linux 4.0 (etch)
DAMAGE: DNS cache poisoning.
SOLUTION: Upgrade to the appropriate version.
______________________________________________________________________________
VULNERABILITY The risk is HIGH. Successful exploitation of the vulnerability
ASSESSMENT: described in this document may result in invalid hostname-to-IP
address mappings in the cache of an affected DNS server. This
may lead of this DNS server to contact with wrong provider of
network services.
______________________________________________________________________________
CVSS 2 BASE SCORE: 9.3
TEMPORAL SCORE: 7.7
VECTOR: (AV:N/AC:M/Au:N/C:C/I:C/A:C/E:F/RL:OF/RC:C)
______________________________________________________________________________
LINKS:
CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/s-341.shtml
ORIGINAL BULLETIN: http://www.cisco.com/en/US/products/products_security_
advisory09186a00809c2168.shtml
ADDITIONAL LINKS: http://www.debian.org/security/2008/dsa-1617
http://www.debian.org/security/2008/dsa-1619
CVE: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=
CVE-2008-1447
______________________________________________________________________________
REVISION HISTORY:
08/18/2008 - revised S-341 to reflect changes Cisco has made in Cisco Security
Advisory Document ID: 107064 where they added a "Port Address
Translation Considerations" section to highlight the problems and
risks when DNS SErvers are behind network devices performing PAT,
and to add a link to Debian Security Advisories for DSA-1617-1 and
DSA-1619-1 for Debian GNU/Linux 4.0 (etch).
[***** Start Cisco Security Advisory Document ID: 107064 *****]
Cisco Security Advisory: Multiple Cisco Products Vulnerable to DNS Cache Poisoning Attacks
Document ID: 107064
Advisory ID: cisco-sa-20080708-dns
http://www.cisco.com/warp/public/707/cisco-sa-20080708-dns.shtml
Revision 2.0
Last Updated 2008 July 29 1700 UTC (GMT)
For Public Release 2008 July 08 1800 UTC (GMT)
--------------------------------------------------------------------------------
Contents
Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Versions and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of this Notice: FINAL
Distribution
Revision History
Cisco Security Procedures
--------------------------------------------------------------------------------
Summary
Multiple Cisco products are vulnerable to DNS cache poisoning attacks due to their use of insufficiently randomized DNS transaction IDs and UDP source ports in the DNS queries that they produce, which may allow an attacker to more easily forge DNS answers that can poison DNS caches.
To exploit this vulnerability an attacker must be able to cause a vulnerable DNS server to perform recursive DNS queries. Therefore, DNS servers that are only authoritative, or servers where recursion is not allowed, are not affected.
Cisco has released free software updates that address these vulnerabilities.
This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20080708-dns.shtml.
This security advisory is being published simultaneously with announcements from other affected organizations.
[Expand all sections] [Collapse all sections]
Affected Products
Products that cache DNS responses and process DNS messages with the recursion desired (RD) flag set may be vulnerable to a DNS cache poisoning attack depending on implementation of the DNS protocol. Products that process DNS messages with the RD flag set will attempt to answer the question asked on behalf of the client. A product is only affected if using a vulnerable implementation of the DNS protocol, the DNS server functionality for the product is enabled, and the DNS feature for the product is configured to process recursive DNS query messages.
Vulnerable Products
The following Cisco products are capable of acting as DNS servers and have been found to have the DNS implementation weakness that makes some types of DNS cache poisoning attacks more likely to succeed:
Cisco IOS Software
A device that is running Cisco IOS Software will be affected if it is running a vulnerable version and if it is acting as a DNS server.
All Cisco IOS Software releases that support the DNS server functionality and that have not had their DNS implementation improved are affected. For information about specific fixed versions, please refer to the Software Versions and Fixes section.
A device that is running Cisco IOS Software is configured to act as a DNS server if the command ip dns server is present in the configuration. This command is not enabled by default.
Cisco Network Registrar
All Cisco Network Registrar versions are affected, and DNS services are enabled by default.
The DNS server on CNR is enabled via the command-line interface (CLI) commands server dns enable start-on-reboot or dns enable start-on-reboot or via the web management interface in the Servers page by selecting the appropriate "Start," "Stop," or "Reload" button.
Cisco Application and Content Networking System
All Cisco Application and Content Networking System (ACNS) versions are affected; DNS services are disabled by default.
ACNS is configured to act as a DNS server if the command dns enable is present in the configuration.
Cisco Global Site Selector Used in Combination with Cisco Network Registrar
The Cisco Global Site Selector (GSS) is affected when it is used in combination with Cisco Network Registrar software to provide a more complete DNS solution. Fixed software would come in the form of an update of the Cisco Network Registrar software rather than an update of the GSS software.
Products Confirmed Not Vulnerable
Products that do not offer DNS server capabilities are not affected by this vulnerability.
The Cisco GSS by itself is not affected by this vulnerability. However, it is affected when it is used with Cisco Network Registrar software.
No other Cisco products are currently known to be affected by these vulnerabilities.
Top of the section Close Section
Details
The Domain Name System is an integral part of networks that are based on TCP/IP such as the Internet. Simply stated, the Domain Name System is a hierarchical database that contains mappings of hostnames and IP addresses. The DNS protocol is part of the TCP/IP protocol suite and allows DNS clients to query the DNS database to resolve hostnames to IP addresses.
A DNS server is an application that implements the DNS protocol and that has the ability to respond to queries made by DNS clients. When handling a query from a DNS client, a DNS server can look into its portion of the global DNS database (if the query is for a portion of the DNS database for which the DNS server is authoritative), or it can relay the query to other DNS servers (if it is configured to do so and if the query is for a portion of the DNS database for which the DNS server is not authoritative.)
Because of the processing time and bandwidth that is associated with handling a DNS query, most DNS servers locally store responses that are received from other DNS servers. The area where these responses are stored locally is called a "cache." Once a response is stored in a cache, the DNS server can use the locally stored response for a certain time (called the "time to live") before having to query DNS servers again to refresh the local (cached) copy of the response.
A DNS cache poisoning attack is an attack in which an entry in the DNS cache of a DNS server is changed so the IP address associated with a hostname in the cache does not point to the correct place. For example, if www.example.com is mapped to the IP address 192.168.0.1 and this mapping is present in the cache of a DNS server, an attacker who succeeds in poisoning the DNS cache of this server may be able to map www.example.com to 10.0.0.1 instead. If this happens, a user who is trying to visit www.example.com may end up contacting the wrong web server.
Although DNS cache poisoning attacks are not new, a security researcher recently presented a technique that allows an attacker to mount successful DNS cache poisoning attacks with low complexity tools and low traffic requirements. This technique exploits a weakness in most implementations of the DNS protocol. The fundamental implementation weakness is that the DNS transaction ID and source port number used to validate DNS responses are not sufficiently randomized and can easily be predicted, which allows an attacker to create forged responses to DNS queries that will match the expected values. The DNS server will consider such responses to be valid.
The following Cisco products that offer DNS server functionality have been found to be susceptible to DNS cache poisoning attacks:
Cisco IOS Software: The vulnerability documented in Cisco bug ID CSCso81854 ( registered customers only) .
Cisco Network Registrar: The vulnerability documented in Cisco bug ID CSCsq01298 ( registered customers only) .
Cisco Application and Content Networking System (ACNS): The vulnerability documented in Cisco bug ID CSCsq21930 ( registered customers only) .
This vulnerability has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2008-1447.
Port Address Translation Considerations
Port Address Translation (PAT) is a form of Network Address Translation (NAT) that allows multiple hosts in a private network to access a public network using a single, public IP address. This is accomplished by rewriting layer 4 information, specifically TCP and UDP source port numbers and checksums, as packets from the private network traverse a network device that is performing PAT. PAT is configured by network administrators and performed by network devices such as firewalls and routers in situations where public IP addresses are limited.
After the initial multi-vendor DNS advisory was published on July 8th, 2008 it was discovered that in some cases the fixes to DNS implementations to use random source ports when sending DNS queries could be negated when such queries traverse PAT devices. The reason for this is that in these cases the network device performing PAT uses a predictable source port allocation policy, such as incremental allocation, when performing the layer 4 rewrite operation that is necessary for PAT. Under this scenario, the fixes made by DNS vendors can be greatly diminished because, while DNS queries seen on the inside network have random source port numbers, the same queries have potentially predictable source port numbers when they leave the private network, depending on the type of traffic that transits through the device.
Several Cisco products are affected by this issue, and if DNS servers are deployed behind one of these affected products operating in PAT mode then the DNS infrastructure may still be at risk even if source port randomization updates have been applied to the DNS servers.
The affected Cisco products, and the respective Cisco bugs that have been created to track the issue, are the following:
Product
Cisco Bug ID
Cisco PIX (6.3.x and earlier)
CSCsr28354 ( registered customers only)
Cisco ASA and Cisco PIX (7.0.x and later)
CSCsr28008 ( registered customers only)
Firewall Services Module (FWSM)
CSCsr29124 ( registered customers only)
Cisco IOS
CSCsr29691 ( registered customers only)
Cisco Content Switching Module (CSM)
CSCsr61220 ( registered customers only)
Fixed software information for these bugs will not be added to this document. Instead, customers should use their regular support channels or the bug tracking features of the Bug Toolkit application on cisco.com to obtain fixed software information.
The above products use an incremental source port allocation policy when performing the source port rewrite operation that is needed for PAT. In the case of Cisco IOS, the original source port will be tried first, but if that port is already allocated and in use for an existing PAT translation then a new port will be incrementally assigned.
Note that traditional NAT, i.e. allocating one public IP address for each private IP address, is not affected by this problem because, unlike PAT, NAT only rewrites layer 3 information and does not modify layer 4 header information of packets traversing the NAT device.
Top of the section Close Section
Vulnerability Scoring Details
Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.
CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.
Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.
Cisco has provided an FAQ to answer additional questions regarding CVSS at
http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html.
Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at
http://intellishield.cisco.com/security/alertmanager/cvss.
CSCso81854, CSCsq01298, CSCsq21930
Calculate the environmental score of CSCso81854/CSCsq01298/CSCsq21930
CVSS Base Score - 6.4
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Network
Low
None
None
Partial
Partial
CVSS Temporal Score - 5.3
Exploitability
Remediation Level
Report Confidence
Functional
Official-Fix
Confirmed
Top of the section Close Section
Impact
Successful exploitation of the vulnerability described in this document may result in invalid hostname-to-IP address mappings in the cache of an affected DNS server. This may lead users of this DNS server to contact the wrong provider of network services. The ultimate impact varies greatly, ranging from a simple denial of service (for example, making www.example.com resolve to 127.0.0.1) to phishing and financial fraud.
Top of the section Close Section
Software Versions and Fixes
When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center (TAC) or your contracted maintenance provider for assistance.
Cisco IOS Software
Each row of the Cisco IOS Software table (below) names a Cisco IOS Software release train. If a given release train is vulnerable, then the earliest possible releases that contain the fix (along with the anticipated date of availability for each, if applicable) are listed in the "First Fixed Release" column of the table. The "Recommended Release" column indicates the releases which have fixes for all the published vulnerabilities at the time of this Advisory. A device running a release in the given train that is earlier than the release in a specific column (less than the First Fixed Release) is known to be vulnerable. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Releases" column of the table.
Major Release
Availability of Repaired Releases
Affected 12.0-Based Releases
First Fixed Release
Recommended Release
12.0
Not Vulnerable
12.0DA
Not Vulnerable
12.0DB
Releases prior to 12.0(7)DB are vulnerable, release 12.0(7)DB and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.0DC
Releases prior to 12.0(7)DC are vulnerable, release 12.0(7)DC and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.0S
Not Vulnerable
12.0SC
Not Vulnerable
12.0SL
Not Vulnerable
12.0SP
Not Vulnerable
12.0ST
Not Vulnerable
12.0SX
Not Vulnerable
12.0SY
Not Vulnerable
12.0SZ
Not Vulnerable
12.0T
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.0W
Not Vulnerable
12.0WC
Vulnerable; contact TAC
12.0WT
Not Vulnerable
12.0XA
Not Vulnerable
12.0XB
Not Vulnerable
12.0XC
Not Vulnerable
12.0XD
Not Vulnerable
12.0XE
Note: Releases prior to 12.0(7)XE1 are vulnerable, release 12.0(7)XE1 and later are not vulnerable;
12.0XF
Not Vulnerable
12.0XG
Not Vulnerable
12.0XH
Not Vulnerable
12.0XI
Not Vulnerable
12.0XJ
Not Vulnerable
12.0XK
Releases prior to 12.0(7)XK2 are vulnerable, release 12.0(7)XK2 and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.0XL
Not Vulnerable
12.0XM
Not Vulnerable
12.0XN
Not Vulnerable
12.0XQ
Not Vulnerable
12.0XR
Releases prior to 12.0(7)XR1 are vulnerable, release 12.0(7)XR1 and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.0XS
Not Vulnerable
12.0XV
Not Vulnerable
12.0XW
Not Vulnerable
Affected 12.1-Based Releases
First Fixed Release
Recommended Release
12.1
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.1AA
Not Vulnerable
12.1AX
Not Vulnerable
12.1AY
Releases prior to 12.1(22)AY1 are vulnerable, release 12.1(22)AY1 and later are not vulnerable;
12.1(22)EA11
12.1AZ
Not Vulnerable
12.1CX
Not Vulnerable
12.1DA
Not Vulnerable
12.1DB
Releases prior to 12.1(4)DB1 are vulnerable, release 12.1(4)DB1 and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.1DC
Releases prior to 12.1(4)DC2 are vulnerable, release 12.1(4)DC2 and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.1E
Not Vulnerable
12.1EA
Releases prior to 12.1(11)EA1 are vulnerable, release 12.1(11)EA1 and later are not vulnerable;
12.1(22)EA11
12.1EB
Not Vulnerable
12.1EC
Not Vulnerable
12.1EO
Not Vulnerable
12.1EU
Not Vulnerable
12.1EV
Not Vulnerable
12.1EW
Not Vulnerable
12.1EX
Note: Releases prior to 12.1(8a)EX are vulnerable, release 12.1(8a)EX and later are not vulnerable;
12.1EY
Not Vulnerable
12.1EZ
Not Vulnerable
12.1GA
Not Vulnerable
12.1GB
Not Vulnerable
12.1T
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.1XA
Not Vulnerable
12.1XB
Not Vulnerable
12.1XC
Releases prior to 12.1(1)XC1 are vulnerable, release 12.1(1)XC1 and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.1XD
Not Vulnerable
12.1XE
Not Vulnerable
12.1XF
Not Vulnerable
12.1XG
Not Vulnerable
12.1XH
Not Vulnerable
12.1XI
Not Vulnerable
12.1XJ
Not Vulnerable
12.1XK
Not Vulnerable
12.1XL
Not Vulnerable
12.1XM
Not Vulnerable
12.1XN
Not Vulnerable
12.1XO
Not Vulnerable
12.1XP
Not Vulnerable
12.1XQ
Not Vulnerable
12.1XR
Not Vulnerable
12.1XS
Not Vulnerable
12.1XT
Not Vulnerable
12.1XU
Not Vulnerable
12.1XV
Not Vulnerable
12.1XW
Not Vulnerable
12.1XX
Not Vulnerable
12.1XY
Not Vulnerable
12.1XZ
Not Vulnerable
12.1YA
Not Vulnerable
12.1YB
Not Vulnerable
12.1YC
Not Vulnerable
12.1YD
Not Vulnerable
12.1YE
Note: Releases prior to 12.1(5)YE1 are vulnerable, release 12.1(5)YE1 and later are not vulnerable;
12.4(19a)
12.4(19b)
12.1YF
Not Vulnerable
12.1YG
Not Vulnerable
12.1YH
Not Vulnerable
12.1YI
Not Vulnerable
12.1YJ
Not Vulnerable
Affected 12.2-Based Releases
First Fixed Release
Recommended Release
12.2
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2B
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2BC
Not Vulnerable
12.2BW
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2BY
Releases prior to 12.2(8)BY are vulnerable, release 12.2(8)BY and later are not vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2BZ
Not Vulnerable
12.2CX
Not Vulnerable
12.2CY
Not Vulnerable
12.2CZ
Vulnerable; contact TAC
12.2DA
Not Vulnerable
12.2DD
Not Vulnerable
12.2DX
Not Vulnerable
12.2EU
Not Vulnerable
12.2EW
Not Vulnerable
12.2EWA
Not Vulnerable
12.2EX
Not Vulnerable
12.2EY
Not Vulnerable
12.2EZ
Not Vulnerable
12.2FX
Not Vulnerable
12.2FY
Not Vulnerable
12.2FZ
Not Vulnerable
12.2IXA
Not Vulnerable
12.2IXB
Not Vulnerable
12.2IXC
Not Vulnerable
12.2IXD
Not Vulnerable
12.2IXE
Not Vulnerable
12.2IXF
Not Vulnerable
12.2JA
Not Vulnerable
12.2JK
Not Vulnerable
12.2MB
Not Vulnerable
12.2MC
Not Vulnerable
12.2S
Not Vulnerable
12.2SB
Not Vulnerable
12.2SBC
Not Vulnerable
12.2SCA
Not Vulnerable
12.2SE
Not Vulnerable
12.2SEA
Not Vulnerable
12.2SEB
Not Vulnerable
12.2SEC
Not Vulnerable
12.2SED
Not Vulnerable
12.2SEE
Not Vulnerable
12.2SEF
Not Vulnerable
12.2SEG
Not Vulnerable
12.2SG
Not Vulnerable
12.2SGA
Not Vulnerable
12.2SL
Not Vulnerable
12.2SM
Not Vulnerable
12.2SO
Not Vulnerable
12.2SRA
Not Vulnerable
12.2SRB
Not Vulnerable
12.2SRC
Not Vulnerable
12.2SU
Not Vulnerable
12.2SV
Not Vulnerable
12.2SVA
Not Vulnerable
12.2SVC
Not Vulnerable
12.2SVD
Not Vulnerable
12.2SW
Not Vulnerable
12.2SX
Not Vulnerable
12.2SXA
Not Vulnerable
12.2SXB
Not Vulnerable
12.2SXD
Not Vulnerable
12.2SXE
Not Vulnerable
12.2SXF
Not Vulnerable
12.2SXH
Not Vulnerable
12.2SXI
Not Vulnerable
12.2SY
Not Vulnerable
12.2SZ
Not Vulnerable
12.2T
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2TPC
Releases prior to 12.2(8)TPC10d are vulnerable, release 12.2(8)TPC10d and later are not vulnerable;
12.2UZ
Not Vulnerable
12.2XA
Not Vulnerable
12.2XB
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2XC
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2XD
Not Vulnerable
12.2XE
Not Vulnerable
12.2XF
Not Vulnerable
12.2XG
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2XH
Not Vulnerable
12.2XI
Not Vulnerable
12.2XJ
Not Vulnerable
12.2XK
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2XL
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2XM
Not Vulnerable
12.2XN
Not Vulnerable
12.2XNA
Not Vulnerable
12.2XO
Not Vulnerable
12.2XQ
Not Vulnerable
12.2XR
Not Vulnerable
12.2XS
Not Vulnerable
12.2XT
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2XU
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2XV
Not Vulnerable
12.2XW
Not Vulnerable
12.2YA
Not Vulnerable
12.2YB
Not Vulnerable
12.2YC
Not Vulnerable
12.2YD
Not Vulnerable
12.2YE
Not Vulnerable
12.2YF
Not Vulnerable
12.2YG
Not Vulnerable
12.2YH
Not Vulnerable
12.2YJ
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2YK
Not Vulnerable
12.2YL
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2YM
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2YN
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2YO
Vulnerable; migrate to any release in 12.2SY
12.2(18)SXF15; Available on 08-AUG-08
12.2YP
Not Vulnerable
12.2YQ
Not Vulnerable
12.2YR
Not Vulnerable
12.2YS
Not Vulnerable
12.2YT
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2YU
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2YV
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2YW
Not Vulnerable
12.2YX
Not Vulnerable
12.2YY
Not Vulnerable
12.2YZ
Not Vulnerable
12.2ZA
Not Vulnerable
12.2ZB
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2ZC
Not Vulnerable
12.2ZD
Vulnerable; contact TAC
12.2ZE
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2ZF
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2ZG
Vulnerable; first fixed in 12.4T
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.2ZH
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.2ZJ
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.2ZL
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.2ZP
Not Vulnerable
12.2ZU
Not Vulnerable
12.2ZY
Not Vulnerable
12.2ZYA
Not Vulnerable
Affected 12.3-Based Releases
First Fixed Release
Recommended Release
12.3
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3B
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3BC
Not Vulnerable
12.3BW
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3EU
Not Vulnerable
12.3JA
Not Vulnerable
12.3JEA
Not Vulnerable
12.3JEB
Not Vulnerable
12.3JEC
Not Vulnerable
12.3JK
Not Vulnerable
12.3JL
Not Vulnerable
12.3JX
Not Vulnerable
12.3T
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3TPC
Vulnerable; contact TAC
12.3VA
Vulnerable; contact TAC
12.3XA
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.3XB
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3XC
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.3XD
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3XE
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.3XF
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3XG
Vulnerable; first fixed in 12.4T
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.3XH
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3XI
Vulnerable; contact TAC
12.3XJ
Vulnerable; first fixed in 12.3YX
12.3(14)YX12
12.4(20)T; Available on 11-JUL-08
12.3XK
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3XQ
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3XR
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.3XS
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.3XU
Not Vulnerable
12.3XW
Vulnerable; first fixed in 12.3YX
12.3(14)YX12
12.4(20)T; Available on 11-JUL-08
12.3XY
Not Vulnerable
12.3YA
Vulnerable; first fixed in 12.4
12.4(19a)
12.4(19b)
12.4(20)T; Available on 11-JUL-08
12.3YD
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.3YF
Vulnerable; first fixed in 12.3YX
12.3(14)YX12
12.4(20)T; Available on 11-JUL-08
12.3YG
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.3YH
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.3YI
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.3YJ
Not Vulnerable
12.3YK
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.3YM
Releases prior to 12.3(14)YM12 are vulnerable, release 12.3(14)YM12 and later are not vulnerable;
12.3(14)YM12
12.3YQ
Not Vulnerable
12.3YS
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.3YT
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.3YU
Vulnerable; first fixed in 12.4XB
12.3YX
12.3(14)YX12
12.3(14)YX12
12.3YZ
Vulnerable; contact TAC
Affected 12.4-Based Releases
First Fixed Release
Recommended Release
12.4
12.4(18b)
12.4(19a)
12.4(19b)
12.4(21)
12.4(19a)
12.4(19b)
12.4JA
Not Vulnerable
12.4JK
Not Vulnerable
12.4JMA
Not Vulnerable
12.4JMB
Not Vulnerable
12.4JMC
Not Vulnerable
12.4JX
Not Vulnerable
12.4MD
12.4(15)MD
12.4(15)MD
12.4MR
12.4(19)MR
12.4(19)MR
12.4SW
Vulnerable; contact TAC
12.4T
12.4(15)T6
12.4(20)T; Available on 11-JUL-08
12.4(20)T; Available on 11-JUL-08
12.4XA
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.4XB
12.4(2)XB10
12.4XC
Vulnerable; contact TAC
12.4XD
12.4(4)XD11; Available on 31-JUL-08
12.4(20)T; Available on 11-JUL-08
12.4XE
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.4XF
Not Vulnerable
12.4XG
Not Vulnerable
12.4XJ
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
12.4XK
Not Vulnerable
12.4XL
12.4(15)XL2
12.4(15)XL2
12.4XM
12.4(15)XM1
12.4(15)XM1
12.4XN
Vulnerable; contact TAC
12.4XQ
Vulnerable; contact TAC
12.4XT
Vulnerable; contact TAC
12.4XV
Vulnerable; contact TAC
12.4XW
12.4(11)XW8
12.4(11)XW6
12.4XY
12.4(15)XY3
12.4XZ
Vulnerable; first fixed in 12.4T
12.4(20)T; Available on 11-JUL-08
Cisco Network Registrar
Affected Release Train
First Fixed Release
Pre-6.1.x
Software has reached End of Support status. Customers running pre-6.1.x versions are advised to upgrade to a newer version as soon as possible.
6.1.x
Upgrade to 6.2.4; available early August 2008
6.2.x
6.2.4; available early August 2008
6.3.x
6.3.1.3 patch; available now
7.0.x
7.0.1; available in early August 2008
Cisco Network Registrar software is available for download at http://www.cisco.com/pcgi-bin/Software/Tablebuild/tablebuild.pl/nr-eval?psrtdcat20e2
Cisco Application and Content Networking System
This issue is fixed in version 5.5.11 of Cisco ACNS software. This release will be available for download from www.cisco.com in early August 2008.
Cisco ACNS 5.5 software is available for download at http://www.cisco.com/pcgi-bin/tablebuild.pl/acns55?psrtdcat20e2.
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Workarounds
There are no workarounds.
Additional information about identification and mitigation of attacks against DNS is in the Cisco Applied Intelligence white paper "DNS Best Practices, Network Protections, and Attack Identification," available at http://www.cisco.com/web/about/security/intelligence/dns-bcp.html.
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Obtaining Fixed Software
Cisco has released free software updates that address these vulnerabilities. Prior to deploying software, customers should consult their maintenance provider or check the software for feature set compatibility and known issues specific to their environment.
Customers may only install and expect support for the feature sets they have purchased. By installing, downloading, accessing or otherwise using such software upgrades, customers agree to be bound by the terms of Cisco's software license terms found at http://www.cisco.com/en/US/products/prod_warranties_item09186a008088e31f.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
Do not contact psirt@cisco.com or security-alert@cisco.com for software upgrades.
Customers with Service Contracts
Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com.
Customers using Third Party Support Organizations
Customers whose Cisco products are provided or maintained through prior or existing agreements with third-party support organizations, such as Cisco Partners, authorized resellers, or service providers should contact that support organization for guidance and assistance with the appropriate course of action in regards to this advisory.
The effectiveness of any workaround or fix is dependent on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround or fix is the most appropriate for use in the intended network before it is deployed.
Customers without Service Contracts
Customers who purchase direct from Cisco but do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC contacts are as follows.
+1 800 553 2447 (toll free from within North America)
+1 408 526 7209 (toll call from anywhere in the world)
e-mail: tac@cisco.com
Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.
Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.
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Exploitation and Public Announcements
The Cisco PSIRT is not aware of malicious use of the vulnerability described in this advisory. Full technical details about the nature of the vulnerability are publicly available and the Metasploit project has published two modules that can exploit this vulnerability.
Although DNS cache poisoning attacks are not new, security researcher Dan Kaminsky of IOActive recently presented a technique that makes DNS cache poisoning attacks more likely to succeed. Cisco would like to thank Dan Kaminsky for notifying vendors about his findings.
Note that vulnerability information for Cisco IOS Software is being provided in this advisory outside of the announced publication schedule for Cisco IOS Software described at http://www.cisco.com/go/psirt due to industry-wide disclosure of the vulnerability.
The multi-vendor advisory published by US-CERT is available at http://www.kb.cert.org/vuls/id/800113 ("VU#800113 - Multiple DNS implementations vulnerable to cache poisoning").
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Status of this Notice: FINAL
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.
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Distribution
This advisory is posted on Cisco's worldwide website at
http://www.cisco.com/warp/public/707/cisco-sa-20080708-dns.shtml.
In addition to worldwide web posting, a text version of this notice is clear-signed with the Cisco PSIRT PGP key and is posted to the following e-mail and Usenet news recipients.
cust-security-announce@cisco.com
first-teams@first.org
bugtraq@securityfocus.com
vulnwatch@vulnwatch.org
cisco@spot.colorado.edu
cisco-nsp@puck.nether.net
full-disclosure@lists.grok.org.uk
comp.dcom.sys.cisco@newsgate.cisco.com
Future updates of this advisory, if any, will be placed on Cisco's worldwide website, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the above URL for any updates.
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Revision History
Revision 2.0
2008-July-28
Added a "Port Address Translation Considerations" section to highlight the problems and risks when DNS servers are behind network devices performing PAT, and to provide information and Cisco bug IDs for Cisco products that can perform PAT and that use predictable source port allocation policies when performing the layer 4 rewrite needed for PAT operation. Updated fixed software availabity dates for Cisco Network Registrar.
Revision 1.2
2008-July-25
Updated the "Exploitation and Public Announcements" section to indicate that full technical details and exploit code are publicly available. Added link to US-CERT Vulnerability Note.
Revision 1.1
2008-July-22
Fixed link to CVSS score calculator. Updated table of fixed software for Cisco Network Registrar. Mention that we are aware of public discussion of the details of the vulnerability. Updated availability information for ACNS software.
Revision 1.0
2008-July-08
Initial public release.
[***** End Cisco Security Advisory Document ID: 107064 *****]
_______________________________________________________________________________
CIAC wishes to acknowledge the contributions of Cisco for the
information contained in this bulletin.
_______________________________________________________________________________
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