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-   -   Any disadvantages of shared secret keys (openvpn) (http://www.linuxquestions.org/questions/linux-security-4/any-disadvantages-of-shared-secret-keys-openvpn-825709/)

natex 08-12-2010 01:55 AM

Any disadvantages of shared secret keys (openvpn)
 
Newbie here dealing with network security (!). I have an ftp/sshd/NX server that I need to access from the internet.

Originally, I accessed my server via ssh and ftp using passwords. I routinely closed these ports remotely via hardware firewall when I didn't need them. The firewall has an https web server (password protected) that is always accessible from the internet. So... I always had at least one port open on the network (firewall's web interface) and sometimes two (sshd) or three (ftpd).

Recently, I added a vpn utilizing shared-secret-keys (no passwords=no brute force attacks), and now can close off ports 21 and 22 to the outside. I think that I can even close the firewall's web interface to the outside too, right? Instead of 2 or 3 open ports I'll have one - which won't be susceptible to brute force attacks. Plus, I can still use all the above services once I'm connected to the vpn.

Aside from the threat of a stolen laptop with the shared-secret-key, am I right thinking that my new setup is more secure? Am I getting a free lunch?

Thanks for any input.

Noway2 08-16-2010 04:15 AM

Is your setup more secure? That is a tough question to answer as it depends on many factors. Based on what you have said, I would say yes for the reason that you are providing less exposure to the outside world by limiting your connections via OpenVPN.

Most of the 'script' attacks either try to brute force port 22 or scan of ssh. You have neither and will bypass most of that. To the best of my knowledge, there isn't a whole lot of interest in OpenVPN's port (UDP on port 1194) so you probably won't attract a lot of interest. Then as you pointed out, connections are based upon a password-less authentication using keys, which is reasonably secure.


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