Summary
Affected Products
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
Some Cisco Catalyst switches, running certain CatOS based software releases, have a vulnerability wherein a buffer overflow in the Telnet option handling can cause the Telnet daemon to crash and result in a switch reload.
This vulnerability can be exploited to initiate a denial of service (DoS) attack. This vulnerability is documented as Cisco bug ID CSCdw19195. There are workarounds available to mitigate the vulnerability.
This advisory is available at http://www.cisco.com/warp/public/707/cisco-sa-20020129-catos-telrcv.shtml.
This section provides details on affected products.
The following Cisco Catalyst Switches are vulnerable:
For the switches above, the following CatOS-based switch software revisions are vulnerable.
|
|
Release 4 code base |
Release 5 code base |
Release 6 code base |
Release 7 code base |
|---|---|---|---|---|
|
Catalyst 6000 series |
Not applicable |
Earlier than 5.5(13) |
Earlier than 6.3(4) |
Earlier than 7.1(2) |
|
Catalyst 5000 series |
Earlier than 4.5(13a) |
Earlier than 5.5(13) |
Earlier than 6.3(4) |
Not applicable |
|
Catalyst 4000 series |
All releases |
Earlier than 5.5(13) |
Earlier than 6.3(4) |
Earlier than 7.1(2) |
To determine your software revision, type show version at the command line prompt.
Cisco's various Catalyst family of switches run CatOS-based releases or IOS-based releases. IOS-based releases are not vulnerable.
The following Cisco Catalyst switches are not vulnerable:
No other Cisco products are currently known to be affected by these vulnerabilities.
Some Cisco Catalyst switches, running certain CatOS-based software releases, have a vulnerability wherein a buffer overflow in the Telnet option handling can cause the Telnet daemon to crash and result in a switch reload. This vulnerability can be exploited to initiate a denial of service (DoS) attack. Once the switch has reloaded, it is still vulnerable and the attack can be repeated as long as the switch is IP reachable on port 23 and has not been upgraded to a fixed version of CatOS switch software.
This vulnerability is documented as Cisco bug ID CSCdw19195, which requires a CCO account to view and can be viewed after 2002 January 30 at 1500 UTC.
This vulnerability can be exploited to produce a denial of service (DoS) attack. When the vulnerability is exploited it can cause the Cisco Catalyst switch to crash and reload.
This vulnerability has been fixed in the following switch software revisions and the fix will be carried forward in all future releases.
|
|
Release 4 code base |
Release 5 code base |
Release 6 code base |
Release 7 code base |
|---|---|---|---|---|
|
Catalyst 6000 series |
Not applicable |
5.5(13) and later |
6.3(4) and later |
7.1(2) and later |
|
Catalyst 5000 series |
4.5(13a) |
5.5(13) and later |
6.3(4) and later |
Not applicable |
|
Catalyst 4000 series |
Not available |
5.5(13) and later |
6.3(4) and later |
7.1(2) and later |
All previous releases must upgrade to the above releases. CatOS switch software release 4.5(13a) for the Catalyst 5000 series is expected on CCO by 2002 February 4. CatOS switch software release 7.1(2) is expected on CCO by 2002 February 6.
Software upgrade can be performed via the console interface. Please refer to software release notes for instructions.
The following workarounds can be implemented.
Cisco has made free software available to address this vulnerability for affected customers. 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/public/sw-license-agreement.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
Do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades.
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 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 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 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.
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.
Refer to 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.
This vulnerability has been exploited to initiate denial of service (DoS) attacks.
This vulnerability was reported by TESO and is detailed at http://www.cert.org/advisories/CA-2001-21.html.
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.
This advisory is posted on Cisco's Worldwide Web site at http://www.cisco.com/warp/public/707/cisco-sa-20020129-catos-telrcv.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 Web site, 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 1.2 |
2002-Feb-05 |
Minor Updates |
|
Revision 1.1 |
2002-Jan-30 |
More Workarounds Added |
|
Revision 1.0 |
2002-Jan-29 |
For Public Release 2002 January 29 at 1500 UTC |
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/go/psirt. This includes instructions for press inquiries regarding Cisco security notices.
| Updated: Feb 05, 2002 | Document ID: 20776 |