Finding ID | Version | Rule ID | IA Controls | Severity |
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V-39402 | SRG-OS-000157-ESXI5 | SV-51260r1_rule | Medium |
Description |
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The Cipher-Block Chaining (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen plain text attacks and must not be used. |
STIG | Date |
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VMware ESXi Server 5.0 Security Technical Implementation Guide | 2013-09-12 |
Check Text ( C-46676r1_chk ) |
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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 '^#' Re-enable lock down mode. If no lines are returned, or the returned ciphers list contains any cipher ending with cbc, this is a finding. |
Fix Text (F-44415r1_fix) |
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Disable lock down mode. Enable the ESXi Shell. Edit the SSH client configuration and add/modify the "Ciphers" configuration (examples of disallowed ciphers: aes128-cbc, aes192-cbc, aes256-cbc, arcfour256blowfish-cbc, cast128-cbc, 3des-cbc). # vi /etc/ssh/ssh_config Re-enable lock down mode. |