The SSH client must be configured to only use FIPS 140-2 approved ciphers.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-39404	SRG-OS-000159-ESXI5	SV-51262r2_rule		Medium

Description
DoD information systems are required to use FIPS 140-2 approved ciphers. SSHv2 ciphers meeting this requirement are 3DES and AES.

STIG	Date
VMware ESXi Server 5.0 Security Technical Implementation Guide	2017-01-06

Details

Check Text ( C-46678r2_chk )
Disable lock down mode. Enable the ESXi Shell. Check the SSH client configuration for allowed ciphers. # grep -i ciphers /etc/ssh/ssh_config | grep -v '^#' If the returned ciphers list contains any cipher not starting with 3des or aes, this is a finding. If the /etc/ssh/ssh_config file does not exist or the Ciphers option is not set, this is not a finding. Re-enable lock down mode.

Fix Text (F-44417r1_fix)
Disable lock down mode. Enable the ESXi Shell. Edit the SSH client configuration and add/modify the "Ciphers" configuration (example: 3des-ctr, aes128-ctr, aes192-ctr, aes256-ctr). # vi /etc/ssh/ssh_config Re-enable lock down mode.