CVE-2021-34696

Cisco ASR 900 and ASR 920 Series Aggregation Services Routers Access Control List Bypass Vulnerability

Severity Score

5.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect programming of hardware when an ACL is configured using a method other than the configuration CLI. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.

Una vulnerabilidad en la programación de la lista de control de acceso (ACL) de Cisco ASR 900 and ASR 920 Series Aggregation Services Routers podría permitir a un atacante remoto no autenticado omitir una ACL configurada. Esta vulnerabilidad es debido a la programación incorrecta del hardware cuando se configura una ACL mediante un método distinto de la CLI de configuración. Un atacante podría explotar esta vulnerabilidad al intentar enviar tráfico mediante un dispositivo afectado. Una explotación con éxito podría permitir al atacante omitir una ACL en el dispositivo afectado

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2021-06-15 CVE Reserved
2021-09-23 CVE Published
2024-06-07 EPSS Updated
2024-11-07 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-284: Improper Access Control

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-asr900acl-UeEyCxkv	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 Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 902 Search vendor "Cisco" for product "Asr 902"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 903 Search vendor "Cisco" for product "Asr 903"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 907 Search vendor "Cisco" for product "Asr 907"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-10sz-pd Search vendor "Cisco" for product "Asr 920-10sz-pd"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-10sz-pd R Search vendor "Cisco" for product "Asr 920-10sz-pd R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-12cz-a Search vendor "Cisco" for product "Asr 920-12cz-a"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-12cz-a R Search vendor "Cisco" for product "Asr 920-12cz-a R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-12cz-d Search vendor "Cisco" for product "Asr 920-12cz-d"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-12cz-d R Search vendor "Cisco" for product "Asr 920-12cz-d R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-12sz-im Search vendor "Cisco" for product "Asr 920-12sz-im"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-12sz-im R Search vendor "Cisco" for product "Asr 920-12sz-im R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-24sz-im Search vendor "Cisco" for product "Asr 920-24sz-im"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-24sz-im R Search vendor "Cisco" for product "Asr 920-24sz-im R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-24sz-m Search vendor "Cisco" for product "Asr 920-24sz-m"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-24sz-m R Search vendor "Cisco" for product "Asr 920-24sz-m R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-24tz-m Search vendor "Cisco" for product "Asr 920-24tz-m"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-24tz-m R Search vendor "Cisco" for product "Asr 920-24tz-m R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-4sz-a Search vendor "Cisco" for product "Asr 920-4sz-a"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-4sz-a R Search vendor "Cisco" for product "Asr 920-4sz-a R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-4sz-d Search vendor "Cisco" for product "Asr 920-4sz-d"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920-4sz-d R Search vendor "Cisco" for product "Asr 920-4sz-d R"	-	-	Safe
Cisco Search vendor "Cisco"	Ios Xe Search vendor "Cisco" for product "Ios Xe"	<= 17.3.2 Search vendor "Cisco" for product "Ios Xe" and version " <= 17.3.2"	-	Affected	in	Cisco Search vendor "Cisco"	Asr 920u-12sz-im Search vendor "Cisco" for product "Asr 920u-12sz-im"	-	-	Safe