TweetFollow Us on Twitter

MacEnterprise: FileVault in the Enterprise, Part 1

Volume Number: 24 (2008)
Issue Number: 07
Column Tag: Security

MacEnterprise: FileVault in the Enterprise, Part 1

Data security for OS X administrators

By Greg Neagle, MacEnterprise.org

Data Security

Data security is a hot topic in Enterprise IT these days. As laptop usage increases, pushing out traditional desktops, the risk to company data is greater than ever. If a laptop is stolen or lost, the replacement cost of the hardware may be a pittance compared to the value of the data stored on the laptop's hard drive.

Therefore many companies are mandating some sort of data encryption for company laptops. If a laptop is then stolen or lost, the data would be inaccessible to the thief. "Whole-disk encryption" is a direction many companies are moving toward, but as of this writing, there are no shipping products that will encrypt a Mac boot volume (although some companies have products in the beta stage). So Mac administrators must work with what is available: a technology Apple calls "FileVault," which secures users' home directories with AES-128 encryption.

In part one of this series, we'll cover preparation and implementation of FileVault in an enterprise environment.

In part two, we'll examine some of the issues you may encounter when implementing and supporting FileVault in an enterprise environment, and techniques and tools to use to deal with some of these issues.

FileVault - encryption for user data

FileVault works by storing a user's files in an encrypted disk image file. Disk images are familiar to OS X administrators — many large organizations set up their OS X machines by restoring a disk image to the machine's hard drive, and many software installers are distributed in the form of disk image files. FileVault uses a disk image that is encrypted with the user's login password. When the user logs in, his or her password is used to unlock the disk image. The image is then mounted under /Users/<username> and for the most part, looks and behaves like a normal user home folder.

There are two primary risks associated with implementing FileVault for your users. The first is that they forget their password and cannot access their data. Since the password is the same as the login password, this seems an unlikely scenario, but there are other ways a user can lock themselves out of a FileVault-protected account. It's not uncommon for organizations to implement a web page that all users can go to change their password. If, however, a user with a FileVault-protected account does this, the FileVault disk image is not updated with the new password – this only happens if you use the Accounts preferences pane to change your password. Another way the password can get out of sync is if the user has multiple machines, and changes their password on a machine other than the laptop with the FileVault-encrypted home directory. Apple has provided a way for administrators to unlock FileVault disk images – this is the FileVault "master password". We'll look at this later in the article.

The second primary risk associated with FileVault is data corruption. Under Tiger, FileVault-protected home directories are encrypted disk images, and since a disk image is a single file, corruption of that single file can lead to the loss of the entire FileVault home directory. This type of corruption is rare, but is possible. In Leopard, FileVault now uses "sparsebundles" as the disk image format. This stores the disk image data in multiple files within an enclosing directory. Apple claims better performance, and importantly, better reliability, which presumably means that disk image corruption is even less likely. Your best defense against data corruption is backups. Backups are always important for enterprise data, but they are even more important for FileVault-protected data.

Preparing for FileVault

Before implementing FileVault in your organization, you might want to do some prep work. The most important bit of prep work is to set the FileVault master password for all your machines. This is the password you can use to get access to a FileVault-protected disk image if the user's password has been forgotten or is otherwise not available. In order to be useful, you almost certainly want this master password to be the same on all the machines you manage.


10.5's Security Preference pane – FileVault tab

To do this, you'll create a FileVault master password on one machine, and then copy certain files to all your managed machines. Open the Security preference pane and click Set Master Password. Since this will be deployed to all your managed machines, and since changing it (and propagating that change to existing FileVault-protected accounts) is difficult, make sure it's a non-trivial password, and do not make it the same as any other admin or root password you have in use. Use the Password Assistant to check on the quality of your chosen password.

Two new files are created in /Library/Keychains: FileVaultMaster.cer, and FileVaultMaster.keychain.

To implement the FileVault master password on all the machines you manage, simply install these two files on all your managed machines. You can use any method to do this (put them in your install image, using ARD, radmind, FileWave, etc), but make sure they are in place before FileVault is turned on for any accounts on a given machine. If FileVault has been turned on before these FileVaultMaster files are installed, the pre-existing FileVault-protected accounts cannot be unlocked using the FileVault master password you just created.

The second most important preparation task is to ensure you have a method to backup user's home directories. If you are using Mobile Accounts and Portable Home Directories, you can simply back up the network home directories on the server. If you can't use Portable Home Directories, you may decide to use something like Retrospect or Time Machine to directly backup user home directories.

You may or may not want to implement the next preparation task: turning on password hints. If your users forget their passwords, in order to get a prompt to allow an administrator to unlock the account using the master password, Show password hints must be turned on in the Accounts preference pane, under Login Options, or if you are managing your clients via MCX, in Workgroup Manager, manage this Preference under Login->Login Window, checking Show password hint when needed and available. One last option is to do this via command-line, perhaps as part of a script:

sudo defaults write /Library/Preferences/com.apple.loginwindow RetriesUntilHint 3

In Tiger, this setting is labeled Show password hint after 3 attempts to enter a password in Workgroup Manager's preference management settings.

Additionally, the MasterPasswordHint key must exist in the defaults keys for /Library/Preferences/com.apple.loginwindow. Normally, this is set when you create the FileVault master password via the Security preferences pane. But if you simply distribute the /Library/Keychains/FileVaultMaster.cer and /Library/Keychains/FileVaultMaster.keychain files to other machines you manage, this key will probably not be set.

sudo defaults write /Library/Preferences/com.apple.loginwindow MasterPasswordHint ""

will do the job. (It's OK to have an empty hint, but the key must exist.)

Enabling password hints is itself considered a security risk in many organizations, so consider if you really want to do this. If you don't, there is no way from the GUI for an admin to recover a FileVault-protected home directory — but an admin can still do so from the command line.

The final preparation task is training. Train your tech support staff on FileVault, and provide a method for your users to find out more about FileVault as well. The better you document and train, the higher users acceptance will be.

Local preparation

There are a few things you can do on the local machine before turning on FileVault that will increase your odds of success. First, make sure the startup disk is healthy. Run Disk Utility to verify, and if needed, repair the startup disk. Second, minimize the amount of data that needs to be copied to the encrypted disk image - delete unneeded files. Empty the trash. rm -R /Users/username/Library/Caches/* to get rid of cache files. If you use Norton/Symantec AntiVirus, turn off AutoProtect. This will speed up creation of the new disk image and avoid issues where Norton AutoProtect interferes with disk image creation. (But be sure to turn it back on later!)

Finally, make sure there is enough free disk space on the startup disk for the FileVault conversion. When FileVault is enabled for an account, an encrypted disk image is created, everything is copied from the "unencrypted" home directory to the encrypted disk image, and finally the items in the unencrypted home directory are deleted. This means that you must have more free space on the hard drive than the size of the home directory you are encrypting. If the user has 60GB of data in his or her home directory, there needs to be more than 60GB free on the hard drive.

Turning on FileVault

Turning on FileVault is straightforward. Log in as the user for which you'd like to turn on FileVault. In the Security preferences pane, click the "Turn On FileVault..." button. If the preference pane is locked, you'll be asked to enter an admin password (which may effectively prevent users from turning on FileVault by themselves). You'll then be prompted for the user's account password (which may effectively prevent admins from turning on FileVault for users without their involvement). You'll be presented with one last dialog, informing you of the dire consequences that await you should you forget your login password and lose the master password.


FileVault confirmation dialog

New to Leopard is the option to turn on secure virtual memory from this dialog; in both Leopard and Tiger it can also be turned on in the Security preference pane. Also note the check box labled "Use secure erase". You should check this. If you do not, when OS X removes the original home folder after creating the FileVault disk image, it is possible to recover some or all of the data using an unerase or file rescue utility. This could defeat much of the purpose of turning on FileVault.

Once you click "Turn On FileVault" in this final confirmation dialog, the current user will be logged out and the FileVault conversion process will start. If anything interrupts the logout (such as cancelling when asked what to do with an unsaved document), the FileVault conversion will be cancelled and you'll have to visit the Security preference pane to start again from the beginning.

If the FileVault conversion process fails for any reason, the partially-created encrypted disk image is removed, and the original home directory is left untouched. Possible reasons for failure of the FileVault conversion are a full hard drive; drive or file system errors or failures; and anti-virus scanning of the drive image.

Automating FileVault

New to Leopard is the ability to enable FileVault protection when creating new accounts, or creating mobile accounts. This saves a step: you no longer have to create the account, then login and turn on FileVault. More importantly, you can use MCX policies to enforce FileVault so that it is automatically turned on for all new mobile and local accounts.

Enforcing FileVault on mobile accounts is straightforward using Workgroup Manager. There is a new checkbox in Mobility preferences under Account Creation Options, labeled Encrypt contents with FileVault.

Apple doesn't make enforcing FileVault for local accounts quite as easy to discover or implement, but it is possible.

In Workgroup Manager, choose a Computer or ComputerGroup to manage, click the Preferences icon in the toolbar, then select the Details pane. Click the "+" button to add a new preference domain. Navigate to /Applications and double-click on the System Preferences app.

You should now have the com.apple.systempreferences domain available to you, and it should look like this:


Preferences details in Workgroup Manager

Double-click the entry for com.apple.systempreferences, and delete all the imported keys - we don't want any of them. Turn down the Always dictionary, and add a new key like this:


Managing com.apple.systempreferences keys

Save your changes.

Once the updated management settings become available on your managed client machines, you'll see that when creating a new local account, the Turn on FileVault protection checkbox is pre-selected, and disabled so that it cannot be deselected. All new local accounts will automatically have FileVault turned on as they are created.


FileVault enforced for local accounts

To be continued...

We've prepared our infrastructure, enabled FileVault on existing user accounts, and looked at options for enforcing FileVault for all new accounts. In part two of this series, we'll look at some issues you and your users might encounter, and what you can do to manage these issues.


Greg Neagle is a member of the steering committee of the Mac OS X Enterprise Project (macenterprise.org) and is a senior systems engineer at a large animation studio. Greg has been working with the Mac since 1984, and with OS X since its release. He can be reached at gregneagle@mac.com. The MacEnterprise project is a community of IT professionals sharing information and solutions to support Macs in an enterprise. We collaborate on the deployment, management, and integration of Mac OS X client and server computers into multi-platform computing environments.

 
AAPL
$97.67
Apple Inc.
+0.64
MSFT
$44.50
Microsoft Corpora
+0.10
GOOG
$589.02
Google Inc.
-4.33

MacTech Search:
Community Search:

Software Updates via MacUpdate

TinkerTool 5.3 - Expanded preference set...
TinkerTool is an application that gives you access to additional preference settings Apple has built into Mac OS X. This allows to activate hidden features in the operating system and in some of the... Read more
Audio Hijack Pro 2.11.0 - Record and enh...
Audio Hijack Pro drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio with Audio Hijack... Read more
Intermission 1.1.1 - Pause and rewind li...
Intermission allows you to pause and rewind live audio from any application on your Mac. Intermission will buffer up to 3 hours of audio, allowing users to skip through any assortment of audio... Read more
Autopano Giga 3.6 - Stitch multiple imag...
Autopano Giga allows you to stitch 2, 20, or 2,000 images. Version 3.0 integrates impressive new features that will definitely make you adopt Autopano Pro or Autopano Giga: Choose between 9... Read more
Airfoil 4.8.7 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
Microsoft Remote Desktop 8.0.8 - Connect...
With Microsoft Remote Desktop, you can connect to a remote PC and your work resources from almost anywhere. Experience the power of Windows with RemoteFX in a Remote Desktop client designed to help... Read more
xACT 2.30 - Audio compression toolkit. (...
xACT stands for X Aaudio Compression Toolkit, an application that encodes and decodes FLAC, SHN, Monkey’s Audio, TTA, Wavpack, and Apple Lossless files. It also can encode these formats to MP3, AAC... Read more
Firefox 31.0 - Fast, safe Web browser. (...
Firefox for Mac offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals... Read more
Little Snitch 3.3.3 - Alerts you to outg...
Little Snitch gives you control over your private outgoing data. Track background activityAs soon as your computer connects to the Internet, applications often have permission to send any... Read more
Thunderbird 31.0 - Email client from Moz...
As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements... Read more

Latest Forum Discussions

See All

Reddme for iPhone - The Reddit Client (...
Reddme for iPhone - The Reddit Client 1.0 Device: iOS iPhone Category: News Price: $.99, Version: 1.0 (iTunes) Description: Reddme for iPhone is an iOS 7-optimized Reddit client that offers a refreshing new way to experience Reddit... | Read more »
Jacob Jones and the Bigfoot Mystery : Ep...
Jacob Jones and the Bigfoot Mystery : Episode 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Jacob Jones is back in Episode 2 of one of Apples 'Best of 2013' games and an App Store... | Read more »
New Trailer For Outcast Odyssey, A New K...
New Trailer For Outcast Odyssey, A New Kind of Card Battler Posted by Jennifer Allen on July 25th, 2014 [ permalink ] Out this Fall is a new kind of card battle game: Outcast Odyssey. | Read more »
Garfield: Survival of the Fattest Coming...
Garfield: Survival of the Fattest Coming to iOS this Fall Posted by Jennifer Allen on July 25th, 2014 [ permalink ] Who loves lasagna? Me. Also everyone’s favorite grumpy fat cat, Garfield. | Read more »
Happy Flock Review
Happy Flock Review By Andrew Fisher on July 25th, 2014 Our Rating: :: HERD IT ALL BEFOREUniversal App - Designed for iPhone and iPad Underneath the gloss of Happy Flock’s visuals is a game of very little substance. It’s cute, but... | Read more »
Square Register Updates Adds Offline Pay...
Square Register Updates Adds Offline Payments Posted by Ellis Spice on July 25th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Looking For Group – Hearthstone’s Curse...
For the first time since its release (which has thankfully been a much shorter window for iPad players than their PC counterparts), Blizzard’s wildly successful Hearthstone: Heroes of Warcraft CCG is sporting some brand new content: the single... | Read more »
Poptile Review
Poptile Review By Jennifer Allen on July 25th, 2014 Our Rating: :: SIMPLY FUNUniversal App - Designed for iPhone and iPad Simple yet a little bit glorious, Poptile is a satisfying entertaining puzzle game with oodles of the ‘one... | Read more »
Modern Combat 5: Blackout Review
Modern Combat 5: Blackout Review By Brittany Vincent on July 25th, 2014 Our Rating: :: LESS QQ, MORE PEW PEWUniversal App - Designed for iPhone and iPad The fifth entry into the blockbuster Modern Combat series is what mobile... | Read more »
Watch and Share Mobile Gameplay Videos W...
Watch and Share Mobile Gameplay Videos With Kamcord Posted by Jennifer Allen on July 25th, 2014 [ permalink ] iPhone App - Designed for the iPhone, compatible with the iPad | Read more »

Price Scanner via MacPrices.net

iMacs on sale for $150 off MSRP, $250 off for...
Best Buy has iMacs on sale for up to $160 off MSRP for a limited time. Choose free home shipping or free instant local store pickup (if available). Prices are valid for online orders only, in-store... Read more
Mac minis on sale for $100 off MSRP, starting...
Best Buy has Mac minis on sale for $100 off MSRP. Choose free shipping or free instant local store pickup. Prices are for online orders only, in-store prices may vary: 2.5GHz Mac mini: $499.99 2.3GHz... Read more
Global Tablet Market Grows 11% in Q2/14 Notwi...
Worldwide tablet sales grew 11.0 percent year over year in the second quarter of 2014, with shipments reaching 49.3 million units according to preliminary data from the International Data Corporation... Read more
New iPhone 6 Models to Have Staggered Release...
Digitimes’ Cage Chao and Steve Shen report that according to unnamed sources in Apple’s upstream iPhone supply chain, the new 5.5-inch iPhone will be released several months later than the new 4.7-... Read more
New iOS App Helps People Feel Good About thei...
Mobile shoppers looking for big savings at their favorite stores can turn to the Goodshop app, a new iOS app with the latest coupons and deals at more than 5,000 online stores. In addition to being a... Read more
Save on 5th generation refurbished iPod touch...
The Apple Store has Apple Certified Refurbished 5th generation iPod touches available starting at $149. Apple’s one-year warranty is included with each model, and shipping is free. Many, but not all... Read more
What Should Apple’s Next MacBook Priority Be;...
Stabley Times’ Phil Moore says that after expanding its iMac lineup with a new low end model, Apple’s next Mac hardware decision will be how it wants to approach expanding its MacBook lineup as well... Read more
ArtRage For iPhone Painting App Free During C...
ArtRage for iPhone is currently being offered for free (regularly $1.99) during Comic-Con San Diego #SDCC, July 24-27, in celebration of the upcoming ArtRage 4.5 and other 64-bit versions of the... Read more
With The Apple/IBM Alliance, Is The iPad Now...
Almost since the iPad was rolled out in 2010, and especially after Apple made a 128 GB storage configuration available in 2012, there’s been debate over whether the iPad is a serious tool for... Read more
MacBook Airs on sale starting at $799, free s...
B&H Photo has the new 2014 MacBook Airs on sale for up to $100 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels... Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.