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

Chromium 119.0.6044.0 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. List of changes available here. Version for Apple... Read more
Spotify 1.2.21.1104 - Stream music, crea...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more
Tor Browser 12.5.5 - Anonymize Web brows...
Using Tor Browser you can protect yourself against tracking, surveillance, and censorship. Tor was originally designed, implemented, and deployed as a third-generation onion-routing project of the U.... Read more
Malwarebytes 4.21.9.5141 - Adware remova...
Malwarebytes (was AdwareMedic) helps you get your Mac experience back. Malwarebytes scans for and removes code that degrades system performance or attacks your system. Making your Mac once again your... Read more
TinkerTool 9.5 - 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
Paragon NTFS 15.11.839 - Provides full r...
Paragon NTFS breaks down the barriers between Windows and macOS. Paragon NTFS effectively solves the communication problems between the Mac system and NTFS. Write, edit, copy, move, delete files on... Read more
Apple Safari 17 - Apple's Web brows...
Apple Safari is Apple's web browser that comes bundled with the most recent macOS. Safari is faster and more energy efficient than other browsers, so sites are more responsive and your notebook... Read more
Firefox 118.0 - Fast, safe Web browser.
Firefox 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 and casual... Read more
ClamXAV 3.6.1 - Virus checker based on C...
ClamXAV is a popular virus checker for OS X. Time to take control ClamXAV keeps threats at bay and puts you firmly in charge of your Mac’s security. Scan a specific file or your entire hard drive.... Read more
SuperDuper! 3.8 - Advanced disk cloning/...
SuperDuper! is an advanced, yet easy to use disk copying program. It can, of course, make a straight copy, or "clone" - useful when you want to move all your data from one machine to another, or do a... Read more

Latest Forum Discussions

See All

‘Monster Hunter Now’ October Events Incl...
Niantic and Capcom have just announced this month’s plans for the real world hunting action RPG Monster Hunter Now (Free) for iOS and Android. If you’ve not played it yet, read my launch week review of it here. | Read more »
Listener Emails and the iPhone 15! – The...
In this week’s episode of The TouchArcade Show we finally get to a backlog of emails that have been hanging out in our inbox for, oh, about a month or so. We love getting emails as they always lead to interesting discussion about a variety of topics... | Read more »
TouchArcade Game of the Week: ‘Cypher 00...
This doesn’t happen too often, but occasionally there will be an Apple Arcade game that I adore so much I just have to pick it as the Game of the Week. Well, here we are, and Cypher 007 is one of those games. The big key point here is that Cypher... | Read more »
SwitchArcade Round-Up: ‘EA Sports FC 24’...
Hello gentle readers, and welcome to the SwitchArcade Round-Up for September 29th, 2023. In today’s article, we’ve got a ton of news to go over. Just a lot going on today, I suppose. After that, there are quite a few new releases to look at... | Read more »
‘Storyteller’ Mobile Review – Perfect fo...
I first played Daniel Benmergui’s Storyteller (Free) through its Nintendo Switch and Steam releases. Read my original review of it here. Since then, a lot of friends who played the game enjoyed it, but thought it was overpriced given the short... | Read more »
An Interview with the Legendary Yu Suzuk...
One of the cool things about my job is that every once in a while, I get to talk to the people behind the games. It’s always a pleasure. Well, today we have a really special one for you, dear friends. Mr. Yu Suzuki of Ys Net, the force behind such... | Read more »
New ‘Marvel Snap’ Update Has Balance Adj...
As we wait for the information on the new season to drop, we shall have to content ourselves with looking at the latest update to Marvel Snap (Free). It’s just a balance update, but it makes some very big changes that combined with the arrival of... | Read more »
‘Honkai Star Rail’ Version 1.4 Update Re...
At Sony’s recently-aired presentation, HoYoverse announced the Honkai Star Rail (Free) PS5 release date. Most people speculated that the next major update would arrive alongside the PS5 release. | Read more »
‘Omniheroes’ Major Update “Tide’s Cadenc...
What secrets do the depths of the sea hold? Omniheroes is revealing the mysteries of the deep with its latest “Tide’s Cadence" update, where you can look forward to scoring a free Valkyrie and limited skin among other login rewards like the 2nd... | Read more »
Recruit yourself some run-and-gun royalt...
It is always nice to see the return of a series that has lost a bit of its global staying power, and thanks to Lilith Games' latest collaboration, Warpath will be playing host the the run-and-gun legend that is Metal Slug 3. [Read more] | Read more »

Price Scanner via MacPrices.net

Clearance M1 Max Mac Studio available today a...
Apple has clearance M1 Max Mac Studios available in their Certified Refurbished store for $270 off original MSRP. Each Mac Studio comes with Apple’s one-year warranty, and shipping is free: – Mac... Read more
Apple continues to offer 24-inch iMacs for up...
Apple has a full range of 24-inch M1 iMacs available today in their Certified Refurbished store. Models are available starting at only $1099 and range up to $260 off original MSRP. Each iMac is in... Read more
Final weekend for Apple’s 2023 Back to School...
This is the final weekend for Apple’s Back to School Promotion 2023. It remains active until Monday, October 2nd. Education customers receive a free $150 Apple Gift Card with the purchase of a new... Read more
Apple drops prices on refurbished 13-inch M2...
Apple has dropped prices on standard-configuration 13″ M2 MacBook Pros, Certified Refurbished, to as low as $1099 and ranging up to $230 off MSRP. These are the cheapest 13″ M2 MacBook Pros for sale... Read more
14-inch M2 Max MacBook Pro on sale for $300 o...
B&H Photo has the Space Gray 14″ 30-Core GPU M2 Max MacBook Pro in stock and on sale today for $2799 including free 1-2 day shipping. Their price is $300 off Apple’s MSRP, and it’s the lowest... Read more
Apple is now selling Certified Refurbished M2...
Apple has added a full line of standard-configuration M2 Max and M2 Ultra Mac Studios available in their Certified Refurbished section starting at only $1699 and ranging up to $600 off MSRP. Each Mac... Read more
New sale: 13-inch M2 MacBook Airs starting at...
B&H Photo has 13″ MacBook Airs with M2 CPUs in stock today and on sale for $200 off Apple’s MSRP with prices available starting at only $899. Free 1-2 day delivery is available to most US... Read more
Apple has all 15-inch M2 MacBook Airs in stoc...
Apple has Certified Refurbished 15″ M2 MacBook Airs in stock today starting at only $1099 and ranging up to $230 off MSRP. These are the cheapest M2-powered 15″ MacBook Airs for sale today at Apple.... Read more
In stock: Clearance M1 Ultra Mac Studios for...
Apple has clearance M1 Ultra Mac Studios available in their Certified Refurbished store for $540 off original MSRP. Each Mac Studio comes with Apple’s one-year warranty, and shipping is free: – Mac... Read more
Back on sale: Apple’s M2 Mac minis for $100 o...
B&H Photo has Apple’s M2-powered Mac minis back in stock and on sale today for $100 off MSRP. Free 1-2 day shipping is available for most US addresses: – Mac mini M2/256GB SSD: $499, save $100 –... Read more

Jobs Board

Licensed Dental Hygienist - *Apple* River -...
Park Dental Apple River in Somerset, WI is seeking a compassionate, professional Dental Hygienist to join our team-oriented practice. COMPETITIVE PAY AND SIGN-ON Read more
Sublease Associate Optometrist- *Apple* Val...
Sublease Associate Optometrist- Apple Valley, CA- Target Optical Date: Sep 30, 2023 Brand: Target Optical Location: Apple Valley, CA, US, 92307 **Requisition Read more
*Apple* / Mac Administrator - JAMF - Amentum...
Amentum is seeking an ** Apple / Mac Administrator - JAMF** to provide support with the Apple Ecosystem to include hardware and software to join our team and Read more
Child Care Teacher - Glenda Drive/ *Apple* V...
Child Care Teacher - Glenda Drive/ Apple ValleyTeacher Share by Email Share on LinkedIn Share on Twitter Read more
Cashier - *Apple* Blossom Mall - JCPenney (...
Cashier - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Blossom Mall Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.