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The SSH daemon must not allow host-based authentication.


Finding ID Version Rule ID IA Controls Severity
V-217999 RHEL-06-000236 SV-217999r505923_rule Medium
SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.
Red Hat Enterprise Linux 6 Security Technical Implementation Guide 2020-09-03


Check Text ( C-19480r377012_chk )
To determine how the SSH daemon's "HostbasedAuthentication" option is set, run the following command:

# grep -i HostbasedAuthentication /etc/ssh/sshd_config

If no line, a commented line, or a line indicating the value "no" is returned, then the required value is set.
If the required value is not set, this is a finding.
Fix Text (F-19478r377013_fix)
SSH's cryptographic host-based authentication is more secure than ".rhosts" authentication, since hosts are cryptographically authenticated. However, it is not recommended that hosts unilaterally trust one another, even within an organization.

To disable host-based authentication, add or correct the following line in "/etc/ssh/sshd_config":

HostbasedAuthentication no