Christoph's last Weblog entries

[FAIL] Security
2nd June 2010

I'm all for security and really like encryption (my Notebook's harddrive is encrypted, I've recently got a GPG Smartcard, ...) but sometimes you see big failes where security is atemted but doesn't actually secure anything but only hinders the legitimate user.

Today one of these candidates ate way to much of my time again. I'm currently getting more and more used to GNU Emacs and currently experimenting with emacs-jabber. Therefore copying my jabber accounts over from psi. As with these passwords you never type in I couldn't remember some of my jabber passwords -- no problem psi has to store them so it should be easy to get them, right?

Well actually not. The configuration file (XML) had a password entry but all that was in it was just obviously hex-encoded numbers. These numbers turned out to be be 16bit packages of characters that are XOR-ed against the JID So now you have to read them in in junks of 16bit, XOR them against the JID and get the password.

Time to recapitulate what this security helped. I've written a hacky 10 lines C Program that can reliably retrieve passwords from any config file I might come across. Seems you can do the same in 2 lines of perl. Ergo no security at all was added.

Next question: What did it cost? Needed an hour or so of researching the encryption and trial&error out the right program fragment. For nothing gained at all. Fail.

Tags: fail, foss, linux, programmieren, rant.

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