You Can Drive a Bus Through Some Windows 7 Holes
|
One thing new with Windows 7 RTM since the Release Candidate -- is that the default administrator account is now disabled by default (the account was also disabled in Vista SP1 and SP2). When Windows 7 (Ultimate x64 in my case) is installed, the user creates a personal log-in and password, and this account is automatically made part of the local Administrators group. At the same time, a second Administrator user account gets created in the background with no password, but the account is disabled by default. In the RC this account was enabled, but no more. * I discovered this little tidbit as I configured my system for least privilege user mode. After I slid the UAC (User Account Control) slider bar to maximum protection, I logged into the Local Users and Groups dialog to change the name of the Administrator account and add a password. Unfortunately, I failed to notice the account was disabled by default. As a result, once I deleted the Administrators group membership from my personal account, I found I had therefore locked myself out of the ability to access any UAC-protected tools -- such as Computer Management or Add/Remove Programs. As there was no active Administrator account in my case, both UAC and RunAs were useless and there was no active Admin account with which I could actively log on. Then I learned Microsoft only went halfway with this significant change, and, man, the other half is really badly done.
As a last recourse, I rebooted and hit F8 during the OS load to get to the Advanced Boot Options. I selected Windows 7's new "Repair Your Computer" option, which loads a slimmed-down user interface for the recovery tool. I selected my account with my limited rights credentials from a drop-down menu and was presented with a single option: Startup Repair. The tool ran a series of diagnostics -- it didn't say what at that time, but I later learned it was running file-system, disk and registry validation checks -- then presented me with the option to restore the computer using System Restore. I was not allowed to select which System Restore settings to use, although the system appeared to use the most recently saved settings. The restore was completed, and voila, permissions were returned to a workable state. Upon further investigation, however, I found that in the preboot environment I could also log in and effect changes using the otherwise disabled local Administrator account, but only under certain circumstances. Specifically, when no other local administrator accounts are present, the disabled Administrator account appears in the log-in drop-down box and can be suddenly be accessed. And as I mentioned above, even after all these years of Microsoft receiving criticism for this lack of attention to security, the Administrator account has no password by default. An admin logging into the recovery tool has a lot more options at his or her disposal, too. As an admin, I could perform the same auto-fix tests, perform System Restores with the ability to select the settings to use, run a System Image Recovery event to restore from a disk backup, run memory diagnostic tests or access the command line for more possible actions. And from the command line I could change drives over to the main drive (from the pre-executable one) and read anything I wanted, even copy it to a USB stick and take it with me. Certainly, we know that a data thief with physical access to the machine typically means game over. Boot to a LiveCD or a USB stick that can see into NTFS (NT File System), and thieves can take whatever they want. The usual countermeasures are then to block boot from CD or USB at the BIOS, and put a BIOS password on the system. But, heck, now Microsoft puts in the hacking tools for you -- no need for third-party boot media. Users could protect themselves by fully encrypting the drive with BitLocker so the intruder only sees garbage. Oh, wait, that's only for Ultimate and Enterprise customers, not the vast majority of people who will use Home Premium. Never mind. Honestly, it's hard to take Microsoft seriously about the security of its products when you can drive a bus through some of their holes. I know the circumstances of this case were a little unique (who among you plan to remove your admin rights?), but in my book, disabled should mean disabled. Microsoft should NOT be creating as default an admin account with no password, then opening up the account for use in certain situations. Word to the wise: Even though that admin account is disabled, do yourself a favor and put a password on it. You probably won't regret it. * Updated to correct some comparisons with Vista. |


Comments (10)
Sorry, but this is just a load of bull.
In Windows accounts with passwords allow remote access to a computer. So, it makes sense to have admin account without a password and disabled by default.
For those legitimate users who really want to shoot themselves in the foot by revoking their own admin rights there is a last resort of activating otherwise disabled admin account that is still restricted to local access only.
As you've metioned yourself, if a thief gets physcial access your computer "the game is over".
Leaving legitimate users a way to recover their access in this case makes more sense than feeble attempts to deter a bad guy, who would probably start with ripping out your HDD anyways.
Posted by Moose | August 15, 2009 12:04 AM
There's a Group Policy object that can be set to disallow the need for an admin password in the Recovery Console. By default, Win 7 requires the password - the problem is that the password is blank. Since MS deemed it prudent to require a password by default, why wouldn't they take the next step and force a password to exist? It doesn't make sense.
Posted by Andrew Garcia | August 15, 2009 1:21 AM
Let me get this straight. If a user removes admin privileges from all accounts, then they're able to recover by using the default admin account. An attacker could also use the account, but only after a legitimate user had broken the permissions, and only if the attacker has physical access to the machine. Is that the gist?
From your account, it sounds like Win 7 was secure (in this respect) out of the box until you broke it.
Once the security was broken, Win 7 provided a convenient way to recover, but ONLY for someone with physical access, which as you mentioned, makes OS level security a moot point.
This is a minor flaw at worst, and I think there's a case to be made that this is reasonable behavior and not a security flaw at all.
Posted by Brian | August 17, 2009 4:24 PM
I know the circumstances are a little off the beaten path, but the thing that is disturbing me is that an account that is supposed to be disabled and is not by default made to have a password, will open up in some circumstances. The easy fix is of course to put a password on the Admin account. I feel Microsoft should make the user/admin do this as part of the setup.
Posted by Andrew Garcia | August 17, 2009 5:44 PM
These findings are insignificant at best. If you have physical access to a machine running any OS, you can easily get unencrypted files from that hard drive without administrative credentials. This applies to any operating system.
Posted by MarkyD | August 19, 2009 10:32 AM
I agree with Andy
Posted by Anonymous | August 19, 2009 10:39 AM
I share Andy's annoyance with BitLocker being available on only some (the most expensive, of course) flavors of Win7, a regrettable trait it shares with Vista. If Microsoft wants to tout its security chops, why not have BitLocker available on all varieties -- of which there are too many? How many small businesses could qualify to purchase Enterprise edition?
Posted by Stratocaster | August 19, 2009 1:11 PM
You can buy an Enterprise License for as few as 5 computers, last I checked into it. So it's possible to get it...
Posted by Andrew Garcia | August 19, 2009 2:25 PM
If Mark Minasi is correct in his recent newsletter the price difference between Windows 7 Professional and Windows 7 Ultimate is $20.00. So you can have BitLocker for an additional 20 bucks which I think is a way of saving some money if you do not want or need encryption. One must have a Trusted Platform Module 1.2 on the motherboard for BitLocker to function so not all users will be able to run it without an upgrade to their hardware. I am glad that Microsoft has reduced the number of SKU's for Windows 7 down to Starter, Premium, Professional, Ultimate, and Enterprise.
Posted by Chris Knieriem | August 23, 2009 11:37 AM
Of course Windows 7 has holes. There are too many cooks in the kitchen at MS, this we know. The fact that their new OS has holes should be anything but surprising. What I find most humorous is that their encryption software is so wonky that there are reports of it breaking third party apps. I have heard conflicting reports, but do we know how much of Windows 7 was a rewrite and how much was written clean from the ground up?
Posted by Mike | November 13, 2009 12:00 PM