Bug 2086690 (CVE-2021-36368)

Summary: CVE-2021-36368 openssh: possible bypass of fido 2 devices and ssh-askpass
Product: [Other] Security Response Reporter: TEJ RATHI <trathi>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: bdettelb, crypto-team, dbelyavs, dwalsh, jburrell, jjelen, lkundrak, mattias.ellert, tm, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Last Closed: 2022-05-16 13:19:11 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Blocks: 2086696    

Description TEJ RATHI 2022-05-16 13:18:57 UTC
** 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 "this is not an authentication bypass, since nothing is being bypassed."

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