Cable Modem Termination System Authentication Bypass
cisco-sa-20020617-cmts-md5-bypass · NA · Published · Updated
Two issues are described in this security advisory. The first issue involves cable modems not manufactured by Cisco that allow a configuration file to be downloaded from an interface that is not connected to the network of the cable modem's service provider. This historical behavior allows an unauthorized configuration to be downloaded to the cable modem. Cisco is providing a feature in its own software that mitigates this vulnerability. This feature is documented as CSCdx57688. The second issue concerns a vulnerability in Cisco IOS® Software on only the Cisco uBR7200 series and uBR7100 series Universal Broadband Routers. A defect, documented as CSCdx72740, allows the creation of a truncated, invalid configuration file that is improperly accepted as valid by the affected routers. Both of these vulnerabilities have been exploited to steal service by reconfiguring the cable modem to remove bandwidth restrictions. Cisco is making free software upgrades available to address these issues. The most current official copy of this document is available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20020617-cmts-md5-bypass.