CVE-2021-36368 Information

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Description

DISPUTED 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 his is not an authentication bypass since nothing is being bypassed.\

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Reference

https://github.com/openssh/openssh-portable/pull/258 https://docs.ssh-mitm.at/trivialauth.html https://bugzilla.mindrot.org/show_bug.cgi?id=3316 https://www.openssh.com/security.html https://security-tracker.debian.org/tracker/CVE-2021-36368

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

LOW

Availability Impact

NONE

Base Score

NONE

Base Severity

3.7