Datasheet

284
Release Notes for Cisco IOS Release 12.1E on the Catalyst 6500 and Cisco 7600 Supervisor Engine and MSFC
OL-2310-11
Caveats
• A vulnerability in the Transmission Control Protocol (TCP) specification (RFC793) has been
discovered by an external researcher. The successful exploitation enables an adversary to reset any
established TCP connection in a much shorter time than was previously discussed publicly.
Depending on the application, the connection may get automatically re-established. In other cases,
a user will have to repeat the action (for example, open a new Telnet or SSH session). Depending
upon the attacked protocol, a successful attack may have additional consequences beyond
terminated connection which must be considered. This attack vector is only applicable to the
sessions which are terminating on a device (such as a router, switch, or computer) and not to the
sessions that are only passing through the device (for example, transit traffic that is being routed by
a router). In addition, this attack vector does not directly compromise data integrity or
confidentiality.
All Cisco products which contain TCP stack are susceptible to this vulnerability.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml, and it describes this
vulnerability as it applies to Cisco products that run Cisco IOS® software.
A companion advisory that describes this vulnerability for products that do not run Cisco IOS
software is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml.
This problem is resolved in Release 12.1(8b)E19. (CSCed93836, CSCdz84583)
Resolved Caveats in Release 12.1(8b)E18
• A vulnerability in the Transmission Control Protocol (TCP) specification (RFC793) has been
discovered by an external researcher. The successful exploitation enables an adversary to reset any
established TCP connection in a much shorter time than was previously discussed publicly.
Depending on the application, the connection may get automatically re-established. In other cases,
a user will have to repeat the action (for example, open a new Telnet or SSH session). Depending
upon the attacked protocol, a successful attack may have additional consequences beyond
terminated connection which must be considered. This attack vector is only applicable to the
sessions which are terminating on a device (such as a router, switch, or computer) and not to the
sessions that are only passing through the device (for example, transit traffic that is being routed by
a router). In addition, this attack vector does not directly compromise data integrity or
confidentiality.
All Cisco products which contain TCP stack are susceptible to this vulnerability.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-ios.shtml, and it describes this
vulnerability as it applies to Cisco products that run Cisco IOS® software.
A companion advisory that describes this vulnerability for products that do not run Cisco IOS
software is available at
http://www.cisco.com/warp/public/707/cisco-sa-20040420-tcp-nonios.shtml.
This problem is resolved in Release 12.1(8b)E18. (CSCed27956, CSCed38527)
• Cisco products running IOS contain vulnerabilities in the processing of H.323 messages, which are
typically used in packetized voice or multimedia applications. Features such as NAT and IOS
Firewall must inspect H.323 messages and may be vulnerable as well. A test suite has been
developed by the University of Oulu to target this protocol and identify vulnerabilities. Support for
the H.323 protocol was introduced in Cisco IOS Software Release 11.3T, and all later Cisco IOS
releases are affected if configured for various types of Voice/Multimedia Application support. The