A denial-of-service vulnerability exists in Cisco's Internetwork Operating System (IOS). This vulnerability may allow attackers to conduct denial-of-service attacks on an affected device.
Multi Protocol Label Switching (MPLS) is designed to increase the speed of IP packet-forwarding by applying labels to packets. These labels are then used by MPLS enabled routers to make packet forwarding decisions. The Cisco Internetwork Operating System (IOS) implementation of MPLS contains a vulnerability that allows malformed MPLS packets to cause an affected device to reload. Such packets can be sent by an unauthenticated attacker on a local network segment connected to a vulnerable device interface and may result in a denial-of-service condition.
According to the Cisco advisory, this vulnerability affects devices that do not have MPLS Traffic Engineering globally enabled. If MPLS Traffic Engineering is disabled, devices that are configured with an interface that has MPLS disabled are vulnerable to attack via that interface only.
By sending a specially crafted MPLS packet to an affected device, an unauthenticated attacker on a local network segment connected to a vulnerable device interface could cause the device to reload. Repeated exploitation of this vulnerability could lead to a sustained denial-of-service condition.
This vulnerability was reported by the Cisco Systems Product Security Incident Response Team (PSIRT).
This document was written by Damon Morda.
|Date First Published:||2005-01-26|
|Date Last Updated:||2005-01-26 19:14 UTC|