CVE-2020-3119 (AKA: CDPwn)

A vulnerability in the Cisco Discovery Protocol implementation for Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability exists because the Cisco Discovery Protocol parser does not properly validate input for certain fields in a Cisco Discovery Protocol message. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. An successful exploit could allow the attacker to cause a stack overflow, which could allow the attacker to execute arbitrary code with administrative privileges on an affected device. 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 6:44pm UTC reported:

This vulnerability is described as a “Stack overflow” by the original disclosure notice.

An attacker would need to be on the local area network, directly attached to the vulnerable switch running NX-OS. 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. Successful exploitation could create a denial of service of allow the attacker to hop VLANs. The later is effectively bypassing segmentation and would be of great concern within PCI environments where segmentation is mandated through regulations.

Assessed Attacker Value: 3
Assessed Attacker Value: 3Assessed Attacker Value: 4