MGASA-2022-0436

Updated dropbear package fixes a security vulnerability in dbclient:. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.

The fix adds a new option, DisableTrivialAuth, to dbclient to disable this attack vector. Invoke dbclient as "dbclient -o DisableTrivialAuth=yes localhost …" to enable this mitigation on each dbclient invocation.