OL 8 must force a frequent session key renegotiation for SSH connections to the server.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-248868	OL08-00-040161	SV-248868r877398_rule		Medium

Description
Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. Operating systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Session key regeneration limits the chances of a session key becoming compromised.

Description

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied on to provide confidentiality or integrity, and DoD data may be compromised. Operating systems using encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules. Session key regeneration limits the chances of a session key becoming compromised.

STIG	Date
Oracle Linux 8 Security Technical Implementation Guide	2022-12-06

Details

Check Text ( C-52302r858585_chk )
Verify the SSH server is configured to force frequent session key renegotiation with the following command: $ sudo grep -ir RekeyLimit /etc/ssh/sshd_config* RekeyLimit 1G 1h If "RekeyLimit" does not have a maximum data amount and maximum time defined or is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix Text (F-52256r780169_fix)
Configure the system to force a frequent session key renegotiation for SSH connections to the server by adding or modifying the following line in the "/etc/ssh/sshd_config" file: RekeyLimit 1G 1h The SSH daemon must be restarted for the settings to take effect. $ sudo systemctl restart sshd.service