Title

The SSH daemon must not allow host-based authentication. (Cat II impact)

Discussion

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

Check Content

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

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

Additional Identifiers

Rule ID: SV-217999r603264_rule

Vulnerability ID: V-217999

Group Title: SRG-OS-000106

Expert Comments

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