A remote attacker could create a denial of service on the router.
The Cisco Internetwork Operating System (IOS)
is the operating system used by Cisco routers.
Cisco devices support Multichassis Multilink PPP (MMP), which provides the
ability to split and recombine packets across a logical pipe formed
by multiple links.
The Stack Group Bidding Protocol
is a subcomponent of MMP. It listens on UDP port 9900.
A specially crafted UDP packet sent to the SGBP service
could cause the device to freeze and eventually reset,
leading to a denial of service. Cisco IOS 12.0 through 12.4
are affected by this vulnerability if SGBP is enabled.
For more information, see http://www.cisco.com/warp/public/707/cisco-sa-20060118-sgbp.shtml Cisco Security Advisory 20060118-sgbp.