As a result, the recovered original password can be used to mount the BitLocker volume.įor some volumes, Password might not be among protectors used and the volume might be protected with other protectors (e.g. The password recovery process is time-consuming and depends on the password complexity, any knowledge about the password, and your hardware resources available for password recovery, such as GPUs and availability of distributed computing. to recover the original password (using brute-force or dictionary attacks). However, if the memory image does not contain the VMK (the volume was not mounted during the live memory acquisition, the hibernation file had been overwritten, etc.), it is only possible to decrypt the volume with the Password protector, i.e. To summarize, if the memory image contains the VMK, the volume gets decrypted, regardless of the protector type used to encrypt the volume. By extracting this VMK, it is also possible to recover the protectors ( Recovery Key and Startup Key). A sample result is displayed below:Īs shown on the screenshot above, Passware Kit Forensic displays both the Encryption/Recovery key and Startup key (file) protectors, as well as creates a decrypted copy of the volume. It also recovers the Recovery key and Startup key protectors, if available. Passware Kit extracts the VMK (base64 format) from the memory image (or hibernation file), converts it to FVEK, and decrypts the BitLocker volume.
In this case, the VMK resides in memory as well.
When you turn on a computer configured with the default BitLocker settings, Windows reads the encryption key from the TPM chip, mounts the system drive and proceeds with the boot process. Once a live memory image has been created using warm-boot method *, it is possible to use Passware Kit to extract the VMK and decrypt the volume. When Windows displays a standard Windows user login screen, as above, this means that the system BitLocker volume is mounted and the VMK resides in memory. If a given BitLocker volume is mounted, the VMK resides in RAM. Using Memory Images for Instant Decryption of BitLocker Volumes
Operating system volumes cannot use this type of key protector.Īny of these protectors encrypt a BitLocker Volume Master Key (VMK) to generate a Full Volume Encryption Key (FVEK), which is then used to encrypt the volume. Active Directory Domain Services account. BitLocker uses domain authentication to unlock data volumes.It is a sequence of 48 digits divided by dashes. Recovery key. A recovery key also called a numerical password, is stored as a specified file in a USB memory device.A user-supplied password is used to access the volume. TPM+Startup key. BitLocker uses a combination of the TPM and input from a USB memory device that contains an external key.TPM+PIN+Startup key. BitLocker uses a combination of the TPM, a user-supplied PIN, and input from a USB memory device that contains an external key.BitLocker uses input from a USB memory device that contains the external key. A PIN is four to twenty digits or if you allow enhanced PINs, four to twenty letters, symbols, spaces, or numbers. BitLocker uses a combination of the TPM and a user-supplied Personal Identification Number (PIN). In general, TPM-based protectors can only be associated to an operating system volume. If you specify this protector, users can access the encrypted drive as long as it is connected to the system board that hosts the TPM and the system boot integrity is intact. BitLocker uses the computer’s TPM to protect the encryption key. The list of protectors will be displayed as follows:ĭetailed information on each protector type, in accordance with Microsoft documentation, is provided below: (where C: is the name of the mounted BitLocker-encrypted volume) To list the protectors of a given BitLocker volume, type the following command in command-line prompt (cmd): manage-bde -protectors -get C: Active Directory Domain Services (AD DS) account.Recovery key (numerical password on a USB drive).Protectors that can be used to encrypt a BitLocker volume include: This article explains BitLocker protectors and talks about the best ways to get the data decrypted, even for computers that are turned off.