matsdis

I switched to Termux for a while too. It works. But it was a bit too fiddly. (Symlinks and permissions stuff, separate browser window, notification that it is still running, and also I never set it up to start on boot.)

I switched to BasicSync a while ago, can recommend.

Indeed. At least the source PDF (cited in the graphic) has the data:

It’s cute how they think they can control every technology by controlling commercial sales. And this after 3D printing started as this huge RepRap movement where everybody and their friend built their 3D printer from online instructions and rollerblade bearings.

Up next: when buy a 3D printer kit, you have to agree to only flash the unmodified firmware on your Arduino, and not one of the forks from Github. And you are no longer allowed to create your own hardware at home, or tinker with electronics of any kind, or publish instruction how to make your own electronics. And after that, you now need to register yourself before you can use a debugger.

The authenticated encryption of HTTPS similarly protects the CDN-based web clock approach. This avoids situations where an attacker-in-the-middle tampers with insecure NTP responses, messing up your system’s clock.

Almost… there is this fun thing called a delay attack that works despite encryption! (I’ll admit that it’s probably not a practical concern.)

Anyway, the article talks about time measurements through an absurd amount of abstraction layers. Please don’t ever call this “simple” or even “cloud-native time” or the like.

If you start trying to improve this setup you’ll find so many face-palm moments. Like TCP retransmissions (which the article mentions, to be fair). You’d have to use WebRTC to avoid that, which I bet the CDN network doesn’t support. Or the fact that web browser timers have intentionally reduced precision to resist fingerprinting. (Granted, if you are still in the milliseconds range it is not a problem.)

After I fiddle with the firewall rules (or a system install or major upgrade) I usually only do a quick portscan with nmap from another box. (TCP and UDP; only IPv4 only because I disabled IPv6 completely.) There are online port-scan services too, but you never know if they also invite the bots.

I agree with others here that vulnerability-scanning your own applications seems overkill. Like with external virus scanners, I always feel they are just as likely the attack vector themselves. The more complexity, the more risk.

What I do is:

1. Enable unattended system updates (on Debian stable) and automated reboots. And sometimes check if it actually still works.
2. Firewall configuration with a whitelist for public ports, and as a second layer:
3. configure internal services to listen only on localhost, or to filter access by ip/netmask, and
4. put something in front of services that don’t need general public access. (A wireguard tunnel, or HTTP basic auth in your reverse-proxy.)
5. if you expose ssh to the public, make there is some extra step that prevents you from exposing a test user you just created. I’m using the AllowUsers user whitelist, but KbdInteractiveAuthentication no should be good enough too. If the failed login attempts by the bots bother you, you could run sshd on a non-standard port.
6. stop services you no longer use, or at least remove public access.
7. If you have a complex service that needs to be fully public (say a video conference solution, I wouldn’t worry much about a simple static web server) then isolate it from everything else somehow. Ideally on a separate box, make sure it cannot access the internal network, make sure it cannot access any files it doesn’t need. And install those security patches.

Something else I always wanted to do (but never got around doing) is to create a simple canary intrusion detection. Like, putting some important-looking “prod” host into ~/.ssh/config and a private ssh key, and configure the target host to send me a SMS instead when this key tries to log in. (Or even shut everything down automatically.) This should prevent me from becoming part of a botnet for months unnoticed, maybe.

Check out the “tyranny of the rocket equation”.

Or ask Randall Munroe How many model rocket engines would it take to launch a real rocket into space?

I have a router with a few cronjobs like this:

# m h dom mon dow command  
00 20 12 * * echo "check bank transactions (monthly reminder)"  
00 19 15-21 * * test $(date +\%u) -eq 6 && echo "Anki learning reminder"  

Cron will by default send an email with the script output. So you “just” need a non-broken email setup that forwards system emails to your main account. (Assuming you don’t self-host email too.)

This setup is useful because I have a few other cronjobs (backup scripts, and a health check for my own application) that should notify me in case of failure, and I would eventually notice that this is broken by noticing that those “calendar” emails no longer get through.

Reminds me of this Calvin and Hobbes comic about ethics :)

Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.

Interstellar (2014) - Scene that quotes the poem. Now this is where you go for proper theatrical drama.