Unable to decrypt using diskutil while booted from Recovery HD

Number:rdar://14099380 Date Originated:6-8-2013
Status:Closed Resolved:6-14-2014
Product:OS X Product Version:OS X 10.8.4 Build 12E55
Classification:Security Reproducible:Always

It appears that diskutil on Mac OS X 10.8.4's Recovery HD partition no longer can decrypt FileVault 2-encrypted Macs. 

If you boot from a 10.8.4 Recovery HD partition, you can unlock a FileVault 2-encrypted boot drive but you can't decrypt it using diskutil in Termina

Steps to Reproduce:

1. Boot Mac and hold down ⌘-R (Command –R) to boot from the Mac’s Recovery HD partition.

2. Open Terminal.

3. Use "diskutil list" to get the FileVault 2-encrypted volume's UUID.

4. Run any of the following commands:

diskutil cs revert UUID_here -stdinpassphrase

diskutil cs revert UUID_here -passphrase

diskutil corestorage revert UUID_here -recoveryKeychain /path/to/FileVaultMaster.keychain

Expected Results:

Mac should begin decrypting.

Actual Results:

Attempting to decrypt with diskutil with the following commands now results a "The given UUID is not a CoreStorage Logical Volume UUID" error.


Went back to 10.8.3's Recovery HD and saw the same behavior.


All testing done in VMware running OS X VMs

The fact that decrypting using the institutional keychain does not work is particularly worrying. To the best of my knowledge, the *only* way you can decrypt using the institutional keychain is from Recovery HD or Internet Recovery.


Bug resolved.

This issue has been verified as resolved and can be closed. See https://derflounder.wordpress.com/2013/06/11/decrypting-filevault-2-on-mac-os-x-10-8-4-unlock-first-then-decrypt/

Blog post

Added blog post with findings: http://derflounder.wordpress.com/2013/06/08/mac-os-x-10-8-4s-recovery-hd-removes-ability-to-decrypt-filevault-2-encrypted-mac/

Now reproduced on physical hardware.

I've now reproduced my results on a 2011 MacBook Pro.

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