SSH
CVE-2021-36368
LOW
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Lifecycle Timeline
1DescriptionCVE.org
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.
AnalysisAI
An issue was discovered in OpenSSH before 8.9. Rated low severity (CVSS 3.7), this vulnerability is remotely exploitable, no authentication required. This Improper Authentication vulnerability could allow attackers to bypass authentication mechanisms to gain unauthorized access.
Technical ContextAI
This vulnerability is classified as Improper Authentication (CWE-287), which allows attackers to bypass authentication mechanisms to gain unauthorized access. 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. Affected products include: Openbsd Openssh, Debian Debian Linux. Version information: before 8.9..
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Implement multi-factor authentication, enforce strong password policies, use proven authentication frameworks.
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Same weakness CWE-287 – Improper Authentication
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today