OpenSSH BUG: Client Information leak due to use of roaming connection feature
The OpenSSH client is supports an undocumented/unknown feature called roaming:
If connection to SSH server breaks/stucked unexpectedly,
and if server supports roaming, then client is able to reconnect to the server and resume the suspended SSH session.
Roaming feature on OpenSSH clients contain a security flaw which allows a malicious SSH server to steal the client’s private keys.
To disable Roaming feature, refer following simple steps and secure your server.
Add the option ‘UseRoaming no’ in /etc/ssh/ssh_config file and restart ssh service with -oUseRoaming=no included on the ssh command line.
ie, echo ‘UseRoaming no’ >> /etc/ssh/ssh_config
sudo sh -c ‘echo UseRoaming \”no\” >> /etc/ssh/ssh_config’
It’s being reported that it effects only on Centos 7 servers and they can update OpenSSH using yum.
#yum update openssh
For more information read official Bug at Redhat Bugzilla