The sys admin's daily grind – testssl.sh
A Key Role
Back in the day, integrating and function testing an SSL certificate was an easy thing to do. Now, you can use a shell script that talks plain English, despite the Babylonian confusion of key protocols and ciphers.
Web servers with SSL certificates will likely be the rule. The administrator's responsibility for keeping track of which SSL and TLS settings are up to date on which servers tends to grow proportionally. I have found a trusty helper for this task, testssl.sh
[1], a shell script with many capabilities. For example, typing
testssl -U https://<server>
runs scan tests for popular exploits like Heartbleed, Poodle, and Crime (see output in Listing 1), and I can trigger each test option individually. To discover whether a server is vulnerable for Logjam, I would just type:
testssl.sh --logjam <address>
Listing 1
testssl -U https://<server>
To test whether the server offers its ciphers in a defined order (from strong to weak), I type:
testssl -P <address>
Listing 2 shows the strongest encryption method the server was able to negotiate. The script additionally helps me discover whether the server supports HTTP/2 with:
testssl.sh -Y <address>
Listing 2
testssl -P <address>
It might then respond with Service detected: HTTP HTTP2/ALPN http/1.1 (offered).
The tests are not restricted to HTTPS. I can test a mail server like this:
testssl.sh --starttls smtp <address>
which gives me an equally good quality of analysis as for the web protocol – and it is very exhaustive in this case. If you don't specify any parameters testssl.sh runs through the whole arsenal of test routines (Figure 1).
Aha
Finally, a tip from the developer of testssl.sh: If you additionally install the aha [2] tool, you can easily convert the console output to HTML:
testssl.sh <address> | aha > /<Path>/servertest.html
After wrapping this up in a small shell script, I can then use cron to check the TLS and SSL status of my servers on a weekly basis.
Infos
- Testssl.sh: https://github.com/drwetter/testssl.sh
- Aha: https://github.com/theZiz/aha
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
-
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.
-
ZorinOS 17.1 Released, Includes Improved Windows App Support
If you need or desire to run Windows applications on Linux, there's one distribution intent on making that easier for you and its new release further improves that feature.
-
Linux Market Share Surpasses 4% for the First Time
Look out Windows and macOS, Linux is on the rise and has even topped ChromeOS to become the fourth most widely used OS around the globe.
-
KDE’s Plasma 6 Officially Available
KDE’s Plasma 6.0 "Megarelease" has happened, and it's brimming with new features, polish, and performance.
-
Latest Version of Tails Unleashed
Tails 6.0 is based on Debian 12 and includes GNOME 43.
-
KDE Announces New Slimbook V with Plenty of Power and KDE’s Plasma 6
If you're a fan of KDE Plasma, you'll be thrilled to hear they've announced a new Slimbook with an AMD CPU and the latest version of KDE Plasma desktop.
-
Monthly Sponsorship Includes Early Access to elementary OS 8
If you want to get a glimpse of what's in the pipeline for elementary OS 8, just set up a monthly sponsorship to help fund its continued existence.
-
DebConf24 to be Held in South Korea
Busan will be the location of the latest DebConf running July 28 through August 4
-
Fedora Unleashes Atomic Desktops
Fedora has combined its solid distribution with rpm-ostree system to make it possible to deliver a new family of Fedora spins, called Fedora Atomic Desktops.
-
Bootloader Vulnerability Affects Nearly All Linux Distributions
The developers of shim have released a version to fix numerous security flaws, including one that could enable remote control execution of malicious code under certain circumstances.