Title: Cisco IOS BGP Transitive Attribute Denial of Service Vulnerability
Severity: HIGH
Description:
IOS is the firmware designed for Cisco routers. IOS is a router specific firmware designed to allow networkers the ability to configure and control Cisco routers.
A problem in IOS makes it possible for remote users to crash Cisco routers. By crashing the router, it may be possible to deny service to legitimate users of network resources.
During normal operation, Cisco routers using BGP update their routing tables from periodic BGP UPDATE messages.
The problem occurs in the handling of BGP updates by IOS. A BGP UPDATE contains transitive attributes, which detail information about routing transitions. By specifying an unrecognized transitive attribute, IOS becomes unstable, performing an unpredictable activity between crashing upon receiving the packet, or failing later while trying to clear the unrecognized attribute. The router requires power cycling to resume normal operation.
Affected Products:
- Cisco IOS 11.2
- Cisco IOS 11.2(4)XA
- Cisco IOS 11.2(4)XAf
- Cisco IOS 11.2BC
- Cisco IOS 11.2F
- Cisco IOS 11.2GS
- Cisco IOS 11.2P
- Cisco IOS 11.3
- Cisco IOS 11.3AA
- Cisco IOS 11.3DA
- Cisco IOS 11.3DB
- Cisco IOS 11.3HA
- Cisco IOS 11.3NA
- Cisco IOS 11.3T
- Cisco IOS 11.3WA4
- Cisco IOS 12.0
- Cisco IOS 12.0DA
- Cisco IOS 12.0DB
- Cisco IOS 12.0DC
- Cisco IOS 12.0S
- Cisco IOS 12.0T
- Cisco IOS 12.0W5
- Cisco IOS 12.0XA
- Cisco IOS 12.0XB
- Cisco IOS 12.0XC
- Cisco IOS 12.0XD
- Cisco IOS 12.0XE
- Cisco IOS 12.0XF
- Cisco IOS 12.0XG
- Cisco IOS 12.0XH
- Cisco IOS 12.0XI
- Cisco IOS 12.0XJ
References:
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