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Cisco Security Advisory: Cisco CNS Network Registrar Denial of Service Vulnerability ============================================================================= Revision 1.0
For Public Release 2004 December 02 1600 UTC (GMT)
Summary Affected Products Details Impact Software Versions and Fixes Obtaining Fixed Software Workarounds Exploitation and Public Announcements Status of This Notice: FINAL Distribution Revision History Cisco Security Procedures
Cisco CNS Network Registrar Domain Name Service /Dynamic Host Configuration Protocol (DNS/DHCP) server for the Windows Server platforms is vulnerable to a Denial of Service attack when a certain crafted packet sequence is directed to the server. Cisco has made free software available to address this vulnerability for all affected customers.
The vulnerabilities are documented as the following Cisco Bug IDs: CSCeg27625 and CSCeg27614.
This advisory will be posted at http://www.cisco.com/warp/public/707/ cisco-sa-20041202-cnr.shtml.
This advisory will also be posted at the Cisco CNS Network Registrar internal web site at: http://csg.cisco.com/nmtg/insmbu/products/cnr/index.cfm?qsolution= CNR&qsection=Product+Bulletins.
Cisco CNS Network Registrar for Windows NT server and Windows 2000
Two issues are described in this advisory CSCeg27625 and CSCeg27614. Cisco CNS Network Registrar version 6.0 through 184.108.40.206 are affected by CSCeg27625. However, all versions upto and including version 220.127.116.11 are also affected by CSCeg27614 .
Products Confirmed Not Vulnerable
The following Cisco Network Registrar products are not vulnerable to the issues described in this advisory:
No other Cisco products are currently known to be affected by these vulnerabilities.
Cisco CNS Network Registrar is a DNS and DHCP server installed on Windows NT servers and Windows 2000 servers. Two separate vulnerabilities may impact system stability or availability if exploited. These issues are detailed below:
These issues are unrelated to the recent Cisco Security Advisory regarding Cisco IOS DHCP implementation. http://www.cisco.com/warp/public/707/ cisco-sa-20041110-dhcp.shtml These issues are also unrelated to the recent UNIRAS advisory regarding DNS. http://www.uniras.gov.uk/l1/l2/l3/alerts2004/ alert-4004.txt
Exploitation of either CSCeg27625 or CSCeg27614 can result in a denial of service attack, stemming from system resource starvation or unavailability.
The two issues are fixed in the 18.104.22.168 patch release. Releases are available for download to registered customers on CCO at: http://www.cisco.com/cgi-bin/ Software/Tablebuild/tablebuild.pl/nr-eval
Customers who are using Cisco Network Registrar 5.5 versions must request a new license key for the Cisco CNS Network Registrar 6.1.1.x release before obtaining the patched 22.214.171.124 release from CCO. Version 5.5 license keys are incompatible with the Cisco CNS Network Registrar 6.0 or 6.1 software releases. To request a new license key, any customer wishing to upgrade version 5.5 to version 6.1 software should send an electronic mail message to email@example.com, and provide the customer name, address, contact name and existing version 5.5 license key string in the body of the message along with a line indicating `CNR PSIRT upgrade for Windows request'. A new license key will be dispatched via email to the requestor, allowing them to install and upgrade to the patched 126.96.36.199 release using the new license key.
When considering software upgrades, please also consult http://www.cisco.com/ warp/public/707/advisory.html 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") for assistance. TAC contacts are as follows.
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 agreement with third-party support organizations such as Cisco Partners, authorized resellers, or service providers should contact that support organization for assistance with the upgrade, which should be free of charge.
Customers without Service Contracts
Customers who purchase direct from Cisco but who do not hold a Cisco service contract and customers who purchase through third-party vendors but are unsuccessful at obtaining fixed software through their point of sale should get their upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC contacts are as follows.
Please have your product serial number available and give the URL of this notice as evidence of your entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.
Please do not contact either "firstname.lastname@example.org" or "email@example.com" for software upgrades.
See http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for additional TAC contact information, including special localized telephone numbers and instructions and e-mail addresses for use in various languages. 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/public/sw-license-agreement.html, or otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/ sw-usingswc.shtml.
These vulnerabilities can be mitigated by placing access lists on adjacent network devices such as routers or firewalls to block inbound connections to all high or ephemeral port numbers, including the CCM port.
If remote access to the Cisco CNS Network Registrar is required, it is recommended that trusted hosts be explicitly permitted in access control lists, and all other connection attempts blocked. Remote connection CLI ports are tcp 2875 & tcp 2876, and the default port number for CCM is tcp1234, which can also be configured to a different port number. Access lists permitting selective access to these ports from trusted IP addresses can mitigate this vulnerability.
The effectiveness of any workaround 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 is the most appropriate for use in the intended network before it is deployed.
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
The discovery and documentation of this vulnerability was conducted by the Qualys Security Research Team. More information about the Qualys Security Research Team can be found at their website: http://www.qualys.com
THIS ADVISORY IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE ADVISORY OR MATERIALS LINKED FROM THE ADVISORY IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS NOTICE AT ANY TIME.
A stand-alone copy or Paraphrase of the text of this Security Advisory that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.
This advisory will be posted on Cisco's worldwide website at http:// www.cisco.com/warp/public/707/cisco-sa-20041202-cnr.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.
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.
+---------------------------------------------+ | Revision | 2004-December-2 | Initial public | | 1.0 | | release. | +---------------------------------------------+
Complete information on reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco, is available on Cisco's worldwide website at http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html . This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go /psirt.
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