CVE-2019-1918

Cisco IOS XR Software Intermediate System–to–Intermediate System Denial of Service Vulnerability

Severity Score

7.4

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A vulnerability in the implementation of Intermediate System–to–Intermediate System (IS–IS) routing protocol functionality in Cisco IOS XR Software could allow an unauthenticated attacker who is in the same IS-IS area to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of IS–IS link-state protocol data units (PDUs). An attacker could exploit this vulnerability by sending specific link-state PDUs to an affected system to be processed. A successful exploit could allow the attacker to cause incorrect calculations used in the weighted remote shared risk link groups (SRLG) or in the IGP Flexible Algorithm. It could also cause tracebacks to the logs or potentially cause the receiving device to crash the IS–IS process, resulting in a DoS condition.

Una vulnerabilidad en la implementación en la funcionalidad del protocolo de enrutamiento de Intermediate System–to–Intermediate System (IS–IS) en el software IOS XR de Cisco, podría permitir a un atacante no autenticado que se encuentre en la misma área de IS-IS causar una condición de denegación de servicio (DoS). La vulnerabilidad es debido al procesamiento incorrecto de las unidades de datos del protocolo (PDU) de estado de enlace de IS–IS. Un atacante podría explotar esta vulnerabilidad enviando PDU específicas de estado de enlace a un sistema afectado para su procesamiento. Una explotación con éxito podría permitir al atacante causar cálculos incorrectos utilizados en los grupos de enlace de riesgo compartido remoto ponderado (SRLG) o en el Algoritmo Flexible IGP. También podría causar trazas de vuelta en los registros o potencialmente causar que el dispositivo receptor bloquee el proceso IS–IS, resultando en una condición DoS.

*Credits: N/A

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Adjacent

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2018-12-06 CVE Reserved
2019-08-07 CVE Published
2023-03-08 EPSS Updated
2024-09-17 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-20: Improper Input Validation
CWE-682: Incorrect Calculation

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-20190807-iosxr-isis-dos-1918	2020-10-16

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"				>= 6.5.2 < 6.6.3 Search vendor "Cisco" for product "Ios Xr" and version " >= 6.5.2 < 6.6.3"		-		Affected
Cisco Search vendor "Cisco"		Carrier Routing System Search vendor "Cisco" for product "Carrier Routing System"				6.5.1 Search vendor "Cisco" for product "Carrier Routing System" and version "6.5.1"		-		Affected
Cisco Search vendor "Cisco"		Carrier Routing System Search vendor "Cisco" for product "Carrier Routing System"				6.5.3 Search vendor "Cisco" for product "Carrier Routing System" and version "6.5.3"		-		Affected