Cisco Security Advisory-
Multiple vulnerabilities have been identified and fixed in the Cisco Broadband Operating System (CBOS), an operating system for the Cisco 600 family of routers. Any router in the Cisco 600 series family can be made unresponsive by a large amount of HTTP traffic accessing the web-based configuration utility on the router; additionally the web-based configuration utility is enabled by default. This is documented in Cisco Bug IDs CSCdv06084, CSCdv06088, CSCdv06089, and CSCdv06098.
This advisory is available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20010823-cbos-webserver.
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This section provides details on affected products.
Vulnerable Products
The affected models are: 627, 633, 673, 675, 675E, 677, 677i and 678.
These models are vulnerable if they run any of the following, or earlier, CBOS releases: 2.0.1, 2.1.0, 2.1.0a, 2.2.0, 2.2.1, 2.2.1a, 2.3, 2.3.2, 2.3.5, 2.3.7, 2.3.8, 2.3.9, 2.4.1, 2.4.2, and 2.4.2ap.
These defects will be fixed in the following CBOS releases: 2.4.2b and 2.4.3.
Products Confirmed Not Vulnerable
No other releases of CBOS software are affected by this vulnerability. No other Cisco products are affected by this vulnerability.
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CSCdv06084
When the Cisco 600 series router is accessed via telnet via multiple connections, the router will fail to pass traffic, and may become unresponsive to configuration attempts, requiring a reboot to recover to normal operation.
CSCdv06088
When the Cisco 600 series router is accessed via HTTP via multiple connections, the router will fail to pass traffic, and may become unresponsive to configuration attempts, requiring a reboot to recover to normal operation.
CSCdv06089
The web-based configuration utility in Cisco Broadband Operating System (CBOS) binds itself to a TCP port (port 80 unless configured for another port) even when web-based configuration services are disabled. This leaves the Cisco 600 series router vulnerable to CSCdv06088 even when the affected service is apparently disabled.
CSCdv06098
The web-based utility is now disabled by default, allowing customers to choose to enable this configuration option.
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There is no specific workaround for each of these vulnerabilities; however, a workaround exists which has proven a reasonable defense for the CodeRed Worm attack. It is advisable to disable web management on port 80, by setting the web management port to some number greater than 1024, with the following command, replacing the text "number_greater-than_1024" with an actual number.
set web port number_greater-than_1024
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The following table summarizes the CBOS software releases affected by the vulnerabilities described in this notice and scheduled dates on which the earliest corresponding fixed releases will be available.
Major Release
Description or Platform
Availability of Repaired Releases
General Availability (GA)
All releases
All platforms
2.4.3 2001-AUG-23
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This issue is being exploited actively and has been discussed in numerous public announcements and messages. The most common occurrence of exploitation has been via the spread of the CodeRed Worm. References include:
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Revision 1.1
2001-Dec-06
Updated "Obtaining Fixed Software" section
Revision 1.0
2001-Aug-23
Initial public release.
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