CVE-2021-36368

Severity Score

3.7

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is "this is not an authentication bypass, since nothing is being bypassed.

** EN DISPUTA ** Se ha detectado un problema en OpenSSH versiones anteriores a 8.9. Si un cliente está usando autenticación de clave pública con reenvío de agentes pero sin -oLogLevel=verbose, y un atacante ha modificado silenciosamente el servidor para que soporte la opción de autenticación None, entonces el usuario no puede determinar si la autenticación FIDO va a confirmar que el usuario desea conectarse a ese servidor, o que el usuario desea permitir que ese servidor sea conectado a un servidor diferente en nombre del usuario. NOTA: la posición del proveedor es que "esto no es una omisión de la autenticación, ya que no está omitiéndose nada"

*Credits: N/A

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Attack Vector

Network

Attack Complexity

High

Authentication

None

Confidentiality

Partial

Integrity

None

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-07-09 CVE Reserved
2022-03-12 CVE Published
2024-08-04 CVE Updated
2024-10-16 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-287: Improper Authentication

CAPEC

References (5)

URL	Tag	Source
https://bugzilla.mindrot.org/show_bug.cgi?id=3316	Issue Tracking
https://docs.ssh-mitm.at/trivialauth.html	Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2021-36368	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://github.com/openssh/openssh-portable/pull/258	2024-05-17

URL	Date	SRC
https://www.openssh.com/security.html	2024-05-17

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Openbsd Search vendor "Openbsd"		Openssh Search vendor "Openbsd" for product "Openssh"				< 8.9 Search vendor "Openbsd" for product "Openssh" and version " < 8.9"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				11.0 Search vendor "Debian" for product "Debian Linux" and version "11.0"		-		Affected