This reflects the following change made upstream in OpenSSH 9.9: * ssh(1): prefer AES-GCM to AES-CTR mode when selecting a cipher for the connection. The default cipher preference list is now Chacha20/Poly1305, AES-GCM (128/256) followed by AES-CTR (128/192/256).
However, we keep preferring AES-GCM over Chacha/Poly, as hardware acceleration often grants the former a better performance, while there is no security advance of Chacha/Poly usage over 256 bit AES-GCM. Signed-off-by: Peter Müller <[email protected]> --- config/ssh/ssh_config | 2 +- config/ssh/sshd_config | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/config/ssh/ssh_config b/config/ssh/ssh_config index d5f63f315..a248001ff 100644 --- a/config/ssh/ssh_config +++ b/config/ssh/ssh_config @@ -10,7 +10,7 @@ Host * # Only use secure crypto algorithms KexAlgorithms sntrup761x25519-sha512,[email protected],mlkem768x25519-sha256,curve25519-sha256,[email protected],diffie-hellman-group-exchange-sha256 - Ciphers [email protected],aes256-ctr,[email protected],aes192-ctr,[email protected],aes128-ctr + Ciphers [email protected],[email protected],[email protected],aes256-ctr,aes192-ctr,aes128-ctr MACs [email protected],[email protected],[email protected],hmac-sha2-512,hmac-sha2-256,[email protected] # Always visualise server host keys (helps to identify key based MITM attacks) diff --git a/config/ssh/sshd_config b/config/ssh/sshd_config index 7b687457c..25e5b1838 100644 --- a/config/ssh/sshd_config +++ b/config/ssh/sshd_config @@ -21,7 +21,7 @@ MaxStartups 5 # Only allow safe crypto algorithms KexAlgorithms sntrup761x25519-sha512,[email protected],mlkem768x25519-sha256,curve25519-sha256,[email protected],diffie-hellman-group-exchange-sha256 -Ciphers [email protected],aes256-ctr,[email protected],aes192-ctr,[email protected],aes128-ctr +Ciphers [email protected],[email protected],[email protected],aes256-ctr,aes192-ctr,aes128-ctr MACs [email protected],[email protected],[email protected],hmac-sha2-512,hmac-sha2-256,[email protected] # Only allow cryptographically safe SSH host keys (adjust paths if needed) -- 2.51.0
