CVE-2020-3449

Cisco IOS XR Software Additional Paths Denial of Service Vulnerability

Severity Score

4.3

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A vulnerability in the Border Gateway Protocol (BGP) additional paths feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to prevent authorized users from monitoring the BGP status and cause the BGP process to stop processing new updates, resulting in a denial of service (DOS) condition. The vulnerability is due to an incorrect calculation of lexicographical order when displaying additional path information within Cisco IOS XR Software, which causes an infinite loop. An attacker could exploit this vulnerability by sending a specific BGP update from a BGP neighbor peer session of an affected device; an authorized user must then issue a show bgp command for the vulnerability to be exploited. A successful exploit could allow the attacker to prevent authorized users from properly monitoring the BGP status and prevent BGP from processing new updates, resulting in outdated information in the routing and forwarding tables.

Una vulnerabilidad en la funcionalidad de rutas adicionales del Border Gateway Protocol (BGP) del Cisco IOS XR Software podría permitir a un atacante remoto no autenticado impedir que los usuarios autorizados monitoreen el estado de BGP y causar que el proceso de BGP deje de procesar nuevas actualizaciones, resultando en una condición de servicio (DOS). La vulnerabilidad es debido a un cálculo incorrecto del orden lexicográfico al mostrar información de ruta adicional dentro del Cisco IOS XR Software, que causa un bucle infinito. Un atacante podría explotar esta vulnerabilidad mediante el envío de una actualización de BGP específica desde una sesión de un peer vecino de BGP de un dispositivo afectado; un usuario autorizado debe emitir un comando show bgp para que la vulnerabilidad sea explotada. Una explotación con éxito podría permitir al atacante impedir que los usuarios autorizados monitoreen apropiadamente el estado de BGP e impedir que BGP procese nuevas actualizaciones, resultando en información desactualizada en las tablas de enrutamiento y reenvío.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2019-12-12 CVE Reserved
2020-08-17 CVE Published
2023-08-21 EPSS Updated
2024-09-16 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-754: Improper Check for Unusual or Exceptional Conditions

CAPEC

References (1)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-bgp-ErKEqAer	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Cisco Search vendor "Cisco"		Ios Xr Search vendor "Cisco" for product "Ios Xr"				< 7.1.2 Search vendor "Cisco" for product "Ios Xr" and version " < 7.1.2"		-		Affected
Cisco Search vendor "Cisco"		Ios Xr Search vendor "Cisco" for product "Ios Xr"				>= 7.2.0 < 7.2.1 Search vendor "Cisco" for product "Ios Xr" and version " >= 7.2.0 < 7.2.1"		-		Affected
Cisco Search vendor "Cisco"		Ios Xr Search vendor "Cisco" for product "Ios Xr"				>= 7.3.0 < 7.3.1 Search vendor "Cisco" for product "Ios Xr" and version " >= 7.3.0 < 7.3.1"		-		Affected