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
-
Fedora Asahi 40 Remix Available for Macs with Apple Silicon
If you've been anticipating KDE's Plasma 6 for your Apple Silicon-powered Mac, then you're in luck.
-
Red Hat Adds New Deployment Option for Enterprise Linux Platforms
Red Hat has re-imagined enterprise Linux for an AI future with Image Mode.
-
OSJH and LPI Release 2024 Open Source Pros Job Survey Results
See what open source professionals look for in a new role.
-
Proton 9.0-1 Released to Improve Gaming with Steam
The latest release of Proton 9 adds several improvements and fixes an issue that has been problematic for Linux users.
-
So Long Neofetch and Thanks for the Info
Today is a day that every Linux user who enjoys bragging about their system(s) will mourn, as Neofetch has come to an end.
-
Ubuntu 24.04 Comes with a “Flaw"
If you're thinking you might want to upgrade from your current Ubuntu release to the latest, there's something you might want to consider before doing so.
-
Canonical Releases Ubuntu 24.04
After a brief pause because of the XZ vulnerability, Ubuntu 24.04 is now available for install.
-
Linux Servers Targeted by Akira Ransomware
A group of bad actors who have already extorted $42 million have their sights set on the Linux platform.
-
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.