CVE-2020-3120 (AKA: CDPwn)

A vulnerability in the Cisco Discovery Protocol implementation for Cisco FXOS Software, Cisco IOS XR Software, and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a missing check when the affected software processes Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to exhaust system memory, causing the device to reload. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

Recent assessments:

zeroSteiner at February 06, 2020 7:58pm UTC reported:

This vulnerability can be used to trigger a memory exhaustion attack on affected routers within the CDP process. Once the process is out of memory it will crash and the router will reboot causing a denial of service condition for the network. Exploiting this vulnerability would not yield access to sensitive information or bypass segmentation (unless an improperly configured fail over setup is in place).

An attacker would need to be on the local area network, attached to the vulnerable router. This is due to CDP traffic not being forwarded across network boundaries. An attacker leveraging this vulnerability would likely either be physically in the building or have compromised a host which is physically in the building.

Assessed Attacker Value: 2
Assessed Attacker Value: 2Assessed Attacker Value: 4