Cisco IOS XR Software Punt Policer Denial of Service Vulnerability

A vulnerability in the implementation of the punt policer on Trident line cards in Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to overload the CPU on the Trident line card or route processor (RP) and eventually cause a denial of service (DoS) condition for traffic in some queues.

The vulnerability is due to a missing static punt policer for traffic that is destined to a device. An attacker could exploit this vulnerability by sending a large number of specific packets that are destined to an affected device. An exploit could allow the attacker to overload the CPU on the Trident line card or RP and eventually cause a DoS condition for traffic in some queues.

Cisco has confirmed the vulnerability in a security notice and released software updates.

To exploit this vulnerability, an attacker could send a large number of specific packets to be processed by the targeted device. Depending on the location of the device in the environment, the attacker may need access to trusted, internal networks behind a firewall to send specific packets to the device.

Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.