CVE-2021-1534

Cisco Email Security Appliance URL Filtering Bypass Vulnerability

Severity Score

5.3

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device. This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.

Una vulnerabilidad en los mecanismos de protección antispam del software Cisco AsyncOS para Cisco Email Security Appliance (ESA) podría permitir a un atacante remoto no autenticado omitir los filtros de reputación de URL en un dispositivo afectado. Esta vulnerabilidad es debido al procesamiento inapropiado de las URL. Un atacante podría explotar esta vulnerabilidad al diseñar una URL de una manera particular. Una explotación con éxito podría permitir al atacante omitir los filtros de reputación de URL que están configurados para un dispositivo afectado, lo que podría permitir el paso de URLs maliciosas mediante el dispositivo

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

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:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-11-13 CVE Reserved
2021-10-06 CVE Published
2024-06-21 EPSS Updated
2024-09-16 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-20: Improper Input Validation

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-esa-url-bypass-sGcfsDrp	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"	Asyncos Search vendor "Cisco" for product "Asyncos"	< 14.0.1 Search vendor "Cisco" for product "Asyncos" and version " < 14.0.1"	-	Affected	in	Cisco Search vendor "Cisco"	Email Security Appliance C170 Search vendor "Cisco" for product "Email Security Appliance C170"	-	-	Safe
Cisco Search vendor "Cisco"	Asyncos Search vendor "Cisco" for product "Asyncos"	< 14.0.1 Search vendor "Cisco" for product "Asyncos" and version " < 14.0.1"	-	Affected	in	Cisco Search vendor "Cisco"	Email Security Appliance C190 Search vendor "Cisco" for product "Email Security Appliance C190"	-	-	Safe
Cisco Search vendor "Cisco"	Asyncos Search vendor "Cisco" for product "Asyncos"	< 14.0.1 Search vendor "Cisco" for product "Asyncos" and version " < 14.0.1"	-	Affected	in	Cisco Search vendor "Cisco"	Email Security Appliance C380 Search vendor "Cisco" for product "Email Security Appliance C380"	-	-	Safe
Cisco Search vendor "Cisco"	Asyncos Search vendor "Cisco" for product "Asyncos"	< 14.0.1 Search vendor "Cisco" for product "Asyncos" and version " < 14.0.1"	-	Affected	in	Cisco Search vendor "Cisco"	Email Security Appliance C390 Search vendor "Cisco" for product "Email Security Appliance C390"	-	-	Safe
Cisco Search vendor "Cisco"	Asyncos Search vendor "Cisco" for product "Asyncos"	< 14.0.1 Search vendor "Cisco" for product "Asyncos" and version " < 14.0.1"	-	Affected	in	Cisco Search vendor "Cisco"	Email Security Appliance C680 Search vendor "Cisco" for product "Email Security Appliance C680"	-	-	Safe
Cisco Search vendor "Cisco"	Asyncos Search vendor "Cisco" for product "Asyncos"	< 14.0.1 Search vendor "Cisco" for product "Asyncos" and version " < 14.0.1"	-	Affected	in	Cisco Search vendor "Cisco"	Email Security Appliance C690 Search vendor "Cisco" for product "Email Security Appliance C690"	-	-	Safe
Cisco Search vendor "Cisco"	Asyncos Search vendor "Cisco" for product "Asyncos"	< 14.0.1 Search vendor "Cisco" for product "Asyncos" and version " < 14.0.1"	-	Affected	in	Cisco Search vendor "Cisco"	Email Security Appliance C690x Search vendor "Cisco" for product "Email Security Appliance C690x"	-	-	Safe