The article didn&#x27;t make mention multiplexing and MaxSessions defaults in OpenSSH.  The default is 10 which means you auth once, and all subsequent logins are without auth and without syslog entries.  If you manage secure systems and have 2FA, this allows bypassing 2FA and logging.<p>All I have to do is trick your folks into testing a ruby  &#x2F; python &#x2F; perl &#x2F; bash script for me that will drop a key on your machine, fire up ssh using that key and tunnel back to my host.  Now I have full control of your secure (banking, government, eCommerce) environment, completely bypassing 2 factor authentication.  Just one link to one of your email distros and up to 10% of your folks will run it.<p>Combine this with sudo credential caching and now I have root on all of your systems without having to bother finding vulns.<p>Thx to Prandium for the demo of this simple social engineering exploit.