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Tear Apart My Home Server Data Encryption Scheme

Discussion in 'Tech Talk' started by DragonRider, Mar 11, 2007.

  1. DragonRider

    DragonRider

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    In the need for securing my home server I have had to do some thinking. I currently have a Win2003 box with 320gigs Raid 1 and a 160 gig dump drive for downloads and such. I have been using the Raid for backups of data on 2 laptops, my wifes and mine.

    I've been trying to think of a way to use TrueCrypt to create a section on the hard drive that is encrypted, and better, free. I made a 150 gig encrypted file, I use the mount option in Truecrypt and make it mounted in Windows Networking. That way either my wife or myself can backup our data to a secure portion of the server.

    If the server gets unplugged, The encrypted portion becomes locked until I unlock it through true crypt AFTER restarting the server, and reconnecting the share drive. This way also, my wife gets a seamless portion to backup her files with out having to worry about passwords (unless I croak).

    What do you security gurus think of this? It took 6 hours to create the 150 gig secure section, and about 5 to transfer the 120 gigs of data to it. Until this test is over and sure to work. I am running dual backups to a USB Hard drive and the server.

    Thanks,

    John
     
  2. Blitzer

    Blitzer Cool Cat

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    Hmmm, maybe we haven't used your Truecrypt application.

    One issue that stands out is if the encrypted file gets corrupted you are hosed. The same problems existed with the old drive compression technologies from the MSDOS 6 days.
     

  3. DragonRider

    DragonRider

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    Ive done it as a test to see if it was practical, and since a few people want a somewhat easy and viable, yet free scheme to secure their information. I would like any other IT guys see if I missed anything.

    I did say tear me apart, so I am not mad at you, but you didn't help with any potential pitfalls or problems I may have missed.

    If no one ever discussed what someone else did, how would we improve?

    John
     
  4. Furant

    Furant Millennium Member

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    Well, I guess I've never thought of myself as a security guru, but I've used TrueCrypt since its earlier versions (as well as its predecessor E4M). I also have used its sister product DriveCrypt by SecurStar.

    I saw both versions of Blitzer's response ;) and as a piece of anecdotal data, I have never had any of the encrypted files or partitions become corrupt. Now, I don't know what's going on at the bit level, but I would imagine that there's the risk of corruption, but heck, I can't think of one thing in computing that's risk-free.

    It seems like a pretty reasonable scheme if your main concern is someone tapping into your server after physically stealing it. But sitting down at the keyboard they'd have to be nice enough to either dismount the Truecrypt volume or reboot the machine before they tried to steal your data.

    Otherwise, I'd think that any networks that it's connected to would be the biggest vulnerability. Oh, and make sure your TC volume password isn't on a sticky note taped to the monitor.

    Joe
     
  5. Deanster

    Deanster Cheese? CLM Millennium Member

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    As with everything, it's more about your anticipated threat. I'm no guru, but here's my thoughts.

    TrueCrypt, Apple's built-in FileVault, and other similar technology are a good choice if your primary concern is someone getting physical control of the drive outside its normal use location (theft, repair facility, law enforcement, etc.).

    Keeping an encrypted vault on the drive makes it 'impossible' for casual intruders to access items stored within it once they have control of it, and at least more difficult for the hardcore intruder (LE agencies, Nat'l security agencies, etc.).

    As always, security is about the 'weakest link' - encryption is good, but it's only as good as your passphrase, and network authentication/security, depending on whether you have things set up to encrypt/decrypt on the host computer - if so, it's all in the clear on the network.

    I'm hoping you're running a wired network.

    Here's a really interesting article by security guru Bruce Schneier about modern password/passphrase cracking approaches - it's pretty impressive, and can reduce the effort needed to 'brute force' a password by 90%+

    http://www.wired.com/news/columns/0,72458-0.html

    Anyway, the file vault approach makes sense for computers storing any kind of secure data - personal info or credit cards, and for any computer that is taken out in public, like a laptop, even if it has only modestly important data, but it's only one corner of a comprehensive security scheme.

    It's also one that tends to create false confidence, since you need to ensure that unencrypted data never travels across the network, never gets stored unencrypted on destination computers, because anyone who has access to a logged-in node on your network can access the secure partition, etc., etc.

    To have it end-to-end secure, you'll need to get committed about it, right down to locking down inactive machines after just a minute or two of inactivity, or SecureID logins, etc.

    This kind of approach is pretty common for corporate/gov't settings, where someone is watching the process end-to-end, but it's fairly unusual for a home setup. Still worth doing if you've got legitimately sensitive data, but doing it in a way that legitimately improves your real-world security is non-trivial.

    I'd say that based on your description, having the data unencrypted on the laptops, then encrypted on the server, is a little crazy. If it's worth securing the backup, it's worth securing on the drives that wander around in public.

    Personally, I'd encrypt the laptop drives, and then back 'em up to the server, probably without encryption for general data, and with encryption only for sensitive docs/folders.

    Encrypted backups means you are putting a LOT of confidence that the encryption process will work when you really need it. My experience is that plenty of backups end up failing or getting wiped/damaged by the faulty computer that you're trying to restore to, even without adding a layer of complexity like encryption.

    Hope this helps!
     
  6. DragonRider

    DragonRider

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    No, the laptop is data is also encrypted using both a hard disk password and personal files are further encrypted. My wife and I are both used to security and passwords since running a web server and associated business out of the house in the basement for 5 years, after getting hacked once by some chinese guys. I am currently back in school now to pick up a degree in Info System Security.

    One thing I did forget was about temp files on the server. This was mainly an exercise I guess to see if this scheme was doable or not and reasonable. One of my friends in a class tonight said the method to get around that was to put the temp files on an encrypted partition.

    I have looked at other options, and thought I would try to find something that would work with Windows, but still somewhat easy to manage for home users.

    Thank you for the article, it was interesting and provoking. I am going to incorporate some of the methods I hadn't thought of. I could go with a option like Safeboot, but I wanted to see if it would work.

    Thanks all for your time. Again, thinking and learning.

    John
     
  7. Deanster

    Deanster Cheese? CLM Millennium Member

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    OK - you hadn't mentioned any other portion of the 'plan', but if you're encrypting on the laptops, and authenticating through WinServe03, you're probably doing better than average.

    AFAIK, there's no reason not to use DriveCrypt - it does what it does pretty well, though I'm not expert enough to discuss the pros/cons of various approaches to encryption. OTF encryption is a pretty good choice when you feel like you need your data to be secure when you're offline, but not have it be a giant hassle every time you want to touch anything.

    My point wasn't that you shouldn't use it, but rather that it's a good one of what it is, but it does only that one thing. Necessary, but not sufficient.

    I'm mostly a Mac guy these days, and I just check 'encrypted Virtual Memory' to handle the swap file problem. Not sure whether that's a Windows option these days.

    I really liked that article also - a great reminder of how hard it is to have really good passwords that you can still remember. The bit about using phonetic dictionaries to reduce the universe of possibilities to only pronouncable combinations is very clever, as is the 'try every string on the hard drive as a passphrase'. It's a little scary how often those approaches seem to successfuly take advantage of sloppy software or humans, leaving passwords around, or just constructing them in memorable ways.
     
  8. neeko

    neeko

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    Whats the data look like on the wire? Whats the data look like on your page file?