Access your servers securely with a Magic URL
Dance the Two-Step
Earlier I promised to show you how I integrated other security layers with my Magic URL. You briefly saw how I tidied up any fail2ban iptables rules for my dynamic IP address within the main script. Here, I will take a quick look at some two-step authentication configuration.
I will leave you to research the finer details of setting up your two-step verification with the excellent Google Authenticator. However, should you want to add functionality to your Magic URL, wherein IP addresses you know and trust don't have to run through the two-step code-entering process but instead are just asked for a password, then you can use code like this:
echo -e "+ : ALL : 51.15.2.14/24 + : ALL : ${GSM} - : ALL : ALL" > /etc/security/access-local.conf
As you can see, ${GSM}
is the IP address extracted from the Magic URL functionality. If asked, I would say use this with caution and probably only allow fixed-line IP addresses to connect over SSH without running through the two-step process.
The End
Although this approach to opening up access is rudimentary in places, I would like to think it encourages sys admins to develop their lateral thinking. The fact that you can get htaccess to deal with unique IP addresses, rename the Magic URL every minute with a new timestamp derivative (or via another security token), and incorporate other failsafes into a security design raises many questions about how far it's possible to go in securing a server using relatively basic tools.
If you know that you won't be able to carry your SSH key with you for a period of time, you could take two-step authentication scratch codes with you on a piece of paper (or just switch off two-step completely) and still get SSH access relatively securely from anywhere on the planet using this approach.
Something else I might try in the future is spawning another type of task or application with a Magic URL. I didn't want a big clunky Submit button embedded within a web page to allow Magic URL functionality, but you could easily customize this approach to run any service or script you like.
Having read about the Magic URL I use for my CCTV server, I hope you will attempt some of these methods in a creative way to suit your own security needs.
Infos
- htaccess: http://www.htaccess-guide.com
- fail2ban: http://www.fail2ban.org/wiki/index.php/Main_Page
- "Intrusion Detection with fail2ban" by Chris Binnie: http://www.linux-magazine.com/Online/Features/Intrusion-Detection-with-Fail2ban
- "Secure Your Server with TCP Wrappers" by Chris Binnie: http://www.admin-magazine.com/Articles/Secure-Your-Server-with-TCP-Wrappers
- Code for this article: ftp://ftp.linux-magazine.com/pub/listings/magazine/190
- Binnie, Chris,. Linux Server Security: Hack and Defend. Wiley, 2016, http://www.amazon.com/Linux-Server-Security-Hack-Defend/dp/1119277655/
« Previous 1 2 3 4
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
TUXEDO Computers Unveils Linux Laptop Featuring AMD Ryzen CPU
This latest release is the first laptop to include the new CPU from Ryzen and Linux preinstalled.
-
XZ Gets the All-Clear
The back door xz vulnerability has been officially reverted for Fedora 40 and versions 38 and 39 were never affected.
-
Canonical Collaborates with Qualcomm on New Venture
This new joint effort is geared toward bringing Ubuntu and Ubuntu Core to Qualcomm-powered devices.
-
Kodi 21.0 Open-Source Entertainment Hub Released
After a year of development, the award-winning Kodi cross-platform, media center software is now available with many new additions and improvements.
-
Linux Usage Increases in Two Key Areas
If market share is your thing, you'll be happy to know that Linux is on the rise in two areas that, if they keep climbing, could have serious meaning for Linux's future.
-
Vulnerability Discovered in xz Libraries
An urgent alert for Fedora 40 has been posted and users should pay attention.
-
Canonical Bumps LTS Support to 12 years
If you're worried that your Ubuntu LTS release won't be supported long enough to last, Canonical has a surprise for you in the form of 12 years of security coverage.
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.