VA scan for gateway reports CBC ciphers or weak key exchange algorithms or weak mac algorithms
Article ID: 265141
Updated On: 05-01-2024
Products
Issue/Introduction
VA team has scanned the portal servers and reported the following vulnerabilities.
vulnerabilities Names:
SSH Server CBC Mode Ciphers Enabled
SSH Weak Key Exchange Algorithms Enabled
Environment
API Portal Supported releases.
Resolution
1. Add following lines to the /etc/ssh/sshd_config to specify strong ciphers and key Exchange Algorithms explicitly,
#disable CBC mode ciphers
Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com
#disable diffie-hellman-group-exchange-sha1, diffie-hellman-group1-sha1
KexAlgorithms diffie-hellman-group14-sha1,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,curve25519-sha256,curve25519-sha256@libssh.org
#disable weak mac algorithms
MACs hmac-sha2-256,hmac-sha2-512
2. Restart the SSH server
systemctl restart sshd
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