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.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Lyn 1.7.2 - Lightweight image browser an...
Lyn is a fast, lightweight image browser and viewer designed for photographers, graphic artists, and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it delivers... Read more
Tunnelblick 3.6.7beta02 - GUI for OpenVP...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
jAlbum Pro 13.4 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more
calibre 2.65.1 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
jAlbum 13.4 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results - Simply drag and drop photos into groups, choose a design... Read more
Backblaze 4.2.0.966 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Backblaze 4.2.0.966 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Tunnelblick 3.6.7beta02 - GUI for OpenVP...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
calibre 2.65.1 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
jAlbum Pro 13.4 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more

Siralim 2 (RPG / Roguelike) (Games)
Siralim 2 (RPG / Roguelike) 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Siralim 2 is an old-school monster catching RPG. Summon and customize hundreds of creatures to fight for you as... | Read more »
Clean Text (Productivity)
Clean Text 1.0 Device: iOS Universal Category: Productivity Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Gemini - A Journey of Two Stars (Games)
Gemini - A Journey of Two Stars 1.0.1 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1 (iTunes) Description: *** SPECIAL LAUNCH SALE: $2.99 (25% off) *** "A mesmerizing and unexpectedly emotional journey." -- Los... | Read more »
How to get four NFL superstars for your...
Even though you're probably well on your way to building a top notch squad for the new season in Madden NFL Mobile, let's say you could beef it up by adding Rob Gronkowski, Antonio Brown, Von Miller, and Todd Gurley to your roster. That's... | Read more »
Cartoon Network Superstar Soccer: Goal!!...
Cartoon Network Superstar Soccer: Goal!!! – Multiplayer Sports Game Starring Your Favorite Characters 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Become a soccer superstar with your... | Read more »
NFL Huddle: What's new in Topps NFL...
Can you smell that? It's the scent of pigskin in the air, which either means that cliches be damned, pigs are flying in your neck of the woods, or the new NFL season is right around the corner. [Read more] | Read more »
FarmVille: Tropic Escape tips, tricks, a...
Maybe farming is passé in mobile games now. Ah, but farming -- and doing a lot of a other things too -- in an island paradise might be a little different. At least you can work on your tan and sip some pina coladas while tending to your crops. [... | Read more »
Become the King of Avalon in FunPlus’ la...
King Arthur is dead. Considering the legend dates back to the 5th century, it would be surprising if he wasn’t. But in the context of real-time MMO game King of Avalon: Dragon Warfare, Arthur’s death plunges the kingdom into chaos. Evil sorceress... | Read more »
Nightgate (Games)
Nightgate 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: *** Launch Sale: 25% OFF for a limited time! *** In the year 2398, after a great war, a network of intelligent computers known as... | Read more »
3 best fantasy football apps to get you...
Last season didn't go the way you wanted it to in fantasy football. You were super happy following your drafts or auctions, convinced you had outsmarted everyone. You were all set to hustle on the waiver wire, work out some sweet trades, and make... | Read more »

Price Scanner via MacPrices.net

Global Tablet Shipments Projected to Increase...
Digitimes’ Jim Hsiao reports that global tablet shipments will increase by 16.3 percent sequentially to reach nearly 47 million units in 2016′s third quarter, but that volume will still be down over... Read more
Apple’s 2016 Back to School promotion: Free B...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free, and... Read more
Apple refurbished iPad Air 2s available start...
Apple has Certified Refurbished iPad Air 2 available starting at $339. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB Wi-Fi iPad Air 2: $499 - 64GB Wi-Fi iPad... Read more
13-inch 2.5GHz MacBook Pro available for $961...
Overstock has the 13″ 2.5GHz MacBook Pro available for $961.63 including free shipping. Their price is $138 off MSRP. Read more
Clearance 12-inch Retina MacBooks, Apple refu...
Apple has Certified Refurbished 2015 12″ Retina MacBooks available starting at $929. Apple will include a standard one-year warranty with each MacBook, and shipping is free. The following... Read more
BookBook Releases SurfacePad, BookBook &...
BookBook has released three new covers just for iPad Pro: SurfacePad, BookBook and BookBook Rutledge Edition. BookBook for iPad Pro is a gorgeous leather case reminiscent of a vintage sketchbook.... Read more
Clean Text 1.0 for iOS Reduces Text Cleanup a...
Apimac today announced availability of Clean Text for iOS, a tool for webmasters, graphic designers, developers and magazine editors to reduce text cleanup and editing time, and also for any iPhone... Read more
27-inch iMacs on sale for up to $220 off MSRP
B&H Photo has 27″ Apple iMacs on sale for up to $200 off MSRP including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2099 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $1899 $100... Read more
Apple refurbished 13-inch MacBook Airs availa...
Apple has Certified Refurbished 2016 and 2015 13″ MacBook Airs now available starting at $849. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2016 13″ 1.6GHz/8GB/... Read more
Apple refurbished iPad mini 2s available for...
Apple is offering Certified Refurbished iPad mini 2s for up to $80 off the cost of new minis. An Apple one-year warranty is included with each model, and shipping is free: - 16GB iPad mini 2 WiFi: $... Read more

Jobs Board

SW Engineer *Apple* TV - Apple Inc. (United...
The Apple TV team is looking for excellent software engineers with experience in hardware, media management, media playback, content delivery and a passion for Read more
Senior *Apple* Administrator - Pratt Instit...
POSITION SUMMARY: Directs the coordination and standardization of campus-wide Apple systems, including planning, analysis and implementation of Apple -related Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 51218534 Pleasant Hill, California, United States Posted: Aug. 18, 2016 Weekly Hours: 40.00 **Job Summary** As an Apple Read more
*Apple* Retail - Multiple Positions Victor,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Hardware Design Validation Engineer - *Apple...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.