Funny/scary anecdote I experienced a few days ago: most Linux flavors check against the cracklib database when changing passwords, and as I typed in an account password, a brand-new cracklib said it was based on a dictionary word. Now, my passwords are alphanumerical jumble, and they're usually comprised of an alphanumerical jumble "core" that I memorize and then a site-based or computer-based pre- and suffix.
So, let's say for example, my current core is "kgA85kjF3". Then for example, I'd morph that for my Hacker News account to "ZkgA85kjF39!" and my fileserver as "UkgA85kjF3O2". I thought this was a good method of having reasonably long passwords but I'd have to memorize very little per site.
So imagine my surprise, when I created a new password "NkgA85kjF3T3", cracklib found a dictionary word in it. It got worse from there. Through experimentation, I determined that it was indeed the core that was compromised. Any password containing "kgA85kjF3" was compromised.
I have no idea how this happened. If this was not a big cosmic coincidence, if this is not just a random regex filter accident, that means data from at least two known password databases containing my cores has been correlated, and put into cracklib no less. There is really no limit to the imagination regarding what illegitimate databases might contain...
So, let's say for example, my current core is "kgA85kjF3". Then for example, I'd morph that for my Hacker News account to "ZkgA85kjF39!" and my fileserver as "UkgA85kjF3O2". I thought this was a good method of having reasonably long passwords but I'd have to memorize very little per site.
So imagine my surprise, when I created a new password "NkgA85kjF3T3", cracklib found a dictionary word in it. It got worse from there. Through experimentation, I determined that it was indeed the core that was compromised. Any password containing "kgA85kjF3" was compromised.
I have no idea how this happened. If this was not a big cosmic coincidence, if this is not just a random regex filter accident, that means data from at least two known password databases containing my cores has been correlated, and put into cracklib no less. There is really no limit to the imagination regarding what illegitimate databases might contain...