I’m a fan of Time-based One-time Password, aka TOTP, as a means of Two-factor authentication. I’m also a fan of the 1password password manager, which I have set up to sync between my various devices: a laptop Mac, an Android phone, and an iPad. A nice feature of 1password is that it will act as an OTP authenticator, if you store the TOTP secret (either copy-pasted as text, or scanned as a QR code that decodes to a URL containing the same text) alongside your password info. So if I’m lying in bed with only my iPad nearby and I need an OTP code to log into something, I don’t have to get up and grab my phone to get it from Google Authenticator. (I do also have the OTPs in Google Authenticator though.) More importantly, this means that none of my devices is a single point of failure; if my phone is stolen or dies, I can still get into stuff because I have the secrets synced to multiple devices, encrypted in transit and at rest by the password manager.
But, this all stops working when your Time-based OTP is generated on a Mac with a clock running over a minute fast!
Continue reading “OTP codes from Mac not working due to Mac clock running fast”
Bruce Schneier summed it up well: the good guys have to secure all the doors and windows; the bad guys only have to find one. In a nutshell, that’s why security is hard. Real-world security has to deal with that problem all the time.
SSH port forwarding is so useful that sometimes you want to daemonize it, to create encrypted tunnels that never go away. But it’s not trivial to do this. Fortunately it is possible with a little fiddling, and I did it using monit.
Continue reading “Managing autossh via monit”
Rails controllers can get out of hand if you’re not very careful. Skinny Controller Fat Model is a great start. But what about handling errors? Isn’t it enough to just let Rails catch your exception and show a 500 Server Error page?
No, it’s not. Falling back on 500 Server Error for everything outside of the “happy path” through your code is sloppy coding.
Continue reading “Proper Error Handling in Rails Controllers”
If you’ve been using SSH for long you’ve probably seen this at least once:
Address 184.108.40.206 maps to www.foobar.com, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
Sometimes this is helpful. Sometimes this is really annoying and incorrect. Assuming you are a moderately well informed sysadmin and know that this message can safely be ignored, you might have been stumped trying to silence it. You may have tried every option in
man ssh_options and even some of your own (
STFU on?) I think I may be able to help.
Continue reading “Silencing pointless reverse DNS warnings from OpenSSH”