kaashif's blog

Programming, software freedom and Unix


How not to run a website

After a few months of running a website, there are a few things I have realised about how I ran my server when it was first delivered, and how I run it now. The changes have been, for the most part, for the better. Needless to say, when I first started out, I was clueless, overeager and far too ambitious with my plans for “the next Facebook” or something

equally stupid. Mistakes were made along the way, and I’ll make sure I never make them again.

Using FTP

Using FTP at all is a mistake, but my blunder was twofold - I had an account with write access to my file store which was not backed up. Worse yet, the account in question had a six character password consisting of letters and numbers which could have been brute-forced within seconds by a decent CPU.

Of course, when I first set up my FTP server, I was thinking more about how cool it was to be able to transfer files using command line FTP clients and how cool that was. It’s not really that cool and one day, the weight of the security vulnerabilities I had exposed came crashing down on me. In every directory of files.kaashif.co.uk, there were an “index.php” and “index.aspx” files containing links to some online Bible shop. It could have been much worse - I could have been hosting my site using FTP to some VPS somewhere and my site could have been turned into an advert for Bibles. Luckily, my server was only set up to serve static files, with no index pages and certainly no PHP or other scripting languages installed.

The fix was simple, I stopped using FTP and went back to using the chrooted Apache server that comes with OpenBSD 5.4. Of course, now that it’s going to be removed from base, I should probably switch to Nginx, but that can wait - OpenBSD’s Apache, while old and probably insecure, isn’t anywhere nearly as bad as having an FTP server with a weak password.

I count myself lucky that I chrooted my account into the FTP user’s home directory. If I hadn’t, the entire machine I was running the server o would have been compromised and I’d have had to spend 10 minutes spinning up a new one. Terrifying to think about.

Backups

As I mentioned, I didn’t back much of anything up. Mostly, my backups consisted of spreading files over every PC I owned in the hopes that none of them would fail. This worked for static, never-changing files like pictures and videos, but had no place as a strategy when dealing with ever-changing code and documents. The first crisis I faced involved a power cut. Now, as you may know, FreeBSD systems use the Unix File System (UFS2) by default. While it’s OK, a far better alternative is ZFS. I was not using ZFS at the time of the power cut, and just happened to be doing something disk IO intensive at the time. This was a recipe for disaster, as this caused the file system on one of my USB disks to die.

Eventually, the power came back on and I had to pick up the pieces. After booting into single-user mode and fscking the disks, all but one disk survived with only a few jumbled inodes here and there. The last disk could not be recovered for some reason. I ran some data recovery tools and I did manage to, eventually, save most of the data, but I learnt three important lessons:

  • Keep 3 copies of everything
  • Keep those copies on different storage media
  • Have some off-site backups

I heard those somewhere (probably from /usr/games/fortune), and it seems reasonable.

Nowadays, I tend to back my storage array to:

  • Another storage array (this is more redundancy than backup)
  • Tarsnap, an online backup site
  • For the really static data, I have a pile of DVDs

It is impossible for me to erase some of those backups without physically destroying them, which can’t be done by accident. I think that, if there is another power cut, I’ll be fine.

Those are the big two things I’ve done. It’s worth noting that, since I only deal in public key authentication, not transmitting passwords over SSL, my site and SSH access to it was not affected by the recent OpenSSL debacle. Perhaps there’s an OpenSSH issue lurking in the shadows, revealing private keys to hackers. That’s unlikely, though, black hats would have already exploited it if such a thing were possible.

In any case, my pile of DVDs are safe from electronic intrusion, unless you count lightning.