Saint LCDPwn, Who Abused the Neighbourhood

Patron of layer-2 discovery protocols, enterprise switches, and everyone who trusts whatever is on the same network.

Life

In December 2022, at Black Hat Europe, researchers presented LCDPwn: new flaws in layer-2 discovery protocols such as Cisco Discovery Protocol on IOS XR. A heap overflow in certain messages let an attacker on the same network segment reload the process, and with it parts of the device. A sequel to the old attacks on the protocols devices exchange between neighbours, trusting without asking.

Prayer

O Saint LCDPwn, who speaks the language of network neighbours, let our switches listen only to those they must. Amen.

How to celebrate

Celebrated by updating IOS XR and disabling discovery protocols where nobody really uses them.

A network neighbour is a neighbour in trouble.

Technical record

Disclosed on: December 8 2022
CVE: CVE-2022-20846 CVE-2021-1521 CVE-2022-20766
CVSS: 6.5
Product: Cisco · Cisco IOS XR Software

A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the Cisco Discovery Protocol process to reload on an affected device. This vulnerability is due to a heap buffer overflow in certain 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 cause a heap overflow, which could cause the Cisco Discovery Protocol process to reload on the device. The bytes that can be written in the buffer overflow are restricted, which limits remote code execution.Note: 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).  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is part of the September 2022 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see .

Sources: blackhat.com · i.blackhat.com

Canonized by Pope Follina I

Saint LCDPwn, Who Abused the Neighbourhood

Life

Prayer

How to celebrate

Technical record

Related saints

Sharing the feast day

The “pwn” family

Same product: macOS

Same year: 2022