CVE-2021-34749

Multiple Cisco Products Server Name Identification Data Exfiltration Vulnerability

Severity Score

8.6

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

A vulnerability in Server Name Identification (SNI) request filtering of Cisco Web Security Appliance (WSA), Cisco Firepower Threat Defense (FTD), and the Snort detection engine could allow an unauthenticated, remote attacker to bypass filtering technology on an affected device and exfiltrate data from a compromised host. This vulnerability is due to inadequate filtering of the SSL handshake. An attacker could exploit this vulnerability by using data from the SSL client hello packet to communicate with an external server. A successful exploit could allow the attacker to execute a command-and-control attack on a compromised host and perform additional data exfiltration attacks.

Una vulnerabilidad en el filtrado de peticiones Server Name Identification (SNI) de Cisco Web Security Appliance (WSA), Cisco Firepower Threat Defense (FTD) y Snort detection engine podría permitir a un atacante no autenticado remoto omitir la tecnología de filtrado en un dispositivo afectado y exfiltrar datos de un host comprometido. Esta vulnerabilidad es debido a un filtrado inadecuado del handshake SSL. Un atacante podría explotar esta vulnerabilidad al usar los datos del paquete de bienvenida del cliente SSL para comunicarse con un servidor externo. Una explotación con éxito podría permitir al atacante ejecutar un ataque de comando y control en un host comprometido y llevar a cabo ataques adicionales de exfiltración de datos.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

High

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:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2021-06-15 CVE Reserved
2021-08-18 CVE Published
2024-05-03 EPSS Updated
2024-11-07 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

CAPEC

References (3)

URL	Tag	Source
https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html	Mailing List

URL	Date	SRC

URL	Date	SRC
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sni-data-exfil-mFgzXqLN	2023-11-07

URL	Date	SRC
https://www.debian.org/security/2023/dsa-5354	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"		Firepower Management Center Search vendor "Cisco" for product "Firepower Management Center"				2.9.18 Search vendor "Cisco" for product "Firepower Management Center" and version "2.9.18"		-		Affected
Cisco Search vendor "Cisco"		Ironport Web Security Appliance Search vendor "Cisco" for product "Ironport Web Security Appliance"				14.5 Search vendor "Cisco" for product "Ironport Web Security Appliance" and version "14.5"		-		Affected
Cisco Search vendor "Cisco"		Firepower Management Center Virtual Appliance Firmware Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware"				6.6.0 Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware" and version "6.6.0"		-		Affected
Cisco Search vendor "Cisco"		Firepower Management Center Virtual Appliance Firmware Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware"				6.7.0 Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware" and version "6.7.0"		-		Affected
Cisco Search vendor "Cisco"		Firepower Management Center Virtual Appliance Firmware Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware"				7.0.0 Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware" and version "7.0.0"		-		Affected
Cisco Search vendor "Cisco"		Firepower Management Center Virtual Appliance Firmware Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware"				7.1.0 Search vendor "Cisco" for product "Firepower Management Center Virtual Appliance Firmware" and version "7.1.0"		-		Affected