VA scan for gateway reports CBC ciphers or weak key exchange algorithms or weak mac algorithms

Products

• CA API Developer Portal
• CA API Gateway

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,[email protected],[email protected]

#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,[email protected]

#disable weak mac algorithms

MACs hmac-sha2-256,hmac-sha2-512

 

2. Restart the SSH server

systemctl restart sshd