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Archive for April, 2012

Dual Booting Windows 7 w/Bitlocker and BackTrack Linux 5. (You SAID WHAT?)

by on Apr.05, 2012, under Security, Tutorials, Whining

Recently, due to laptop thefts at work and the risk of Personally Identifiable Information (PII) loss, I had to make the difficult choice to start a project to force encrypt our user laptops.  So, due to “what do we already own?” , I chose Microsoft Bitlocker for the Windows 7 computers, and FileVault for the Macintosh OSX 10.7 computers.

That seems fine, however, one “snag”…   I use a dual boot Backtrack 5 and Windows 7 machines DAILY at work.  So, being the guy who lives by the rule “Don’t give an order that you’re not willing to follow yourself” kind of guy, I had to figure out how to encrypt my windows side and still boot Backtrack 5.

I got it to work.  I was painful.

take a second to re-read that.  yes, it works, and yes, it caused me pain to make it work.

So, here are the steps I used to make this work:

Step 1: Wipe the drive.  (you should have backed it up if you needed to save something…  I shouldn’t have to tell you that.)

Step 2: Create a partition for the Win7 to be housed.  Make it the first partition.  Leave unallocated space for BackTrack.  (I left 30 gigs for backtrack…  you probably want more, I have a lot of scripts that always put captured data on something external that I mount and encrypt with Truecrypt…)

Step 3: Install Windows7 (or dump your standard image) to that partition.  Mine created a 100MB boot thing before the windows 7 partition, let it do whatever it wants to do, except use that unallocated space you already saved for Backtrack.

Step 4: Boot Windows 7 and test.   Make sure Windows 7 works first! (Well, functions as well as one could expect for Windows)

Step 5: In Windows, run this command from a command prompt: “%windir%\System32\BdeHdCfg.exe” -target default  (this command preps the drive for Bitlocker.)

Step 6: Encrypt the drive via Bitlocker with your pin.  (record the recovery key.  this is the single more important long string of numbers you’ll ever deal with in Windows. Preserve it, protect it.  This key is your life, young padawan…)

Step 7: When it’s done, Boot Windows 7 and test.   Make sure Windows 7 still works!  (Well, functions as well as one could expect for Windows)

Step 8: Pause Bitlocker.   I turned it off.  (this seems to make no sense, but I had a problem testing this that if I tried to encrypt the drive after installing Linux, forget it, it died.)

Step 9: Boot Backtrack 5 DVD/USB key.

Step 10: Install backtrack 5 to that new unallocated partition.   I configured /dev/sda3 as my /boot partition and /dev/sda5 as my root and /dev/sda6 as my swap.  /dev/sda1 was the windows 7 boot partition and /dev/sda2 was my windows 7 system partition)

Step 11: make sure when you install grub, you install it to /dev/sda3.   DO NOT PUT IT IN THE MBR or /dev/sda or /dev/sda1.  If you do, you just screwed yourself.

Step 12: This will only boot to Windows 7 still.   Grab BCDEDIT for windows, and add a boot option to boot linux on /dev/sda3.

Step 13:  Boot Windows 7 and test.   Make sure Windows 7 still works! (Well, functions as well as one could expect for Windows)

Step 14: Boot Backtrack 5 from the windows boot menu.  it should shell to grub, boot it.  Make sure Backtrack 5 works.

Step 15: Boot Windows 7 and turn Bitlocker back on.   (record the recovery key.  this is the single more important long string of numbers you’ll ever deal with in Windows. Preserve it, protect it.  This key is your life, young padawan…)

Step 16: It should present you the windows 7 boot menu, where option 1 is Windows 7 and option 2 is Backtrack Linux then it should now prompt you for your Bitlocker pin.

I can’t stress two things: #1) this took me weeks of wiping the drive to figure this out.  Don’t be shocked if you have to tweek the steps for your specific situation.  #2) that recovery key is the most important thing in this process…

a few notes: (things that make you go Hmmmm…)
1) It asks you to pick which OS first, then prompts you to enter your Bitlocker pin…   You can’t boot linux unless you unlock bitlocker first.  Not sure why, but I’ll call it an “added feature!”  Remember, the linux side is NOT ENCRYPTED!   That means don’t be an *idiot* what you store there, assume it’s accessible if someone takes your laptop.
2) After you update-grub, plan on having your recovery password around for Bitlocker…  it always keeps asking me for it after I update grub, even though it’s installed to the /boot partition. (/dev/sda3 in my case)  Don’t leave your recovery key in your laptop bag, because that defeats the purpose of encrypting it, duh. I can’t stress that enough. The whole “point” is to protect the windows side in case anyone takes your laptop from getting any useful info off it….  Don’t forget the goal while you’re having so much fun messing with this nightmare.

–Bill (General Major Webelo Captain Zapp Brannigan)

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