BitLocker is a full disk encryption feature included with Windows Vista and later. It is designed to protect data by providing encryption for entire volumes and BitCracker helps to play as a Password Cracking tool
BitLocker is a full-disk encryption feature available in recent Windows versions (Vista, 7, 8.1 and 10) Pro and Enterprise. BitCracker is a mono-GPU password cracking tool for memory units encrypted with the password authentication mode of BitLocker.
BitLocker can use three authentication mechanisms in order to implement encryption:
- Transparent operation mode: This mode uses the capabilities of TPM 1.2 hardware to provide for a transparent user experience: the key used for disk encryption is encrypted by the TPM chip and will only be released to the OS loader code if the early boot files appear to be unmodified.
- User authentication mode: This mode requires that the user provide some authentication to the pre-boot environment in the form of a pre-boot PIN or password.
- USB Key Mode: The user must insert a USB device that contains a startup key into the computer to be able to boot the protected OS.
BitCracker is a mono-GPU password cracking tool developed only for volumes encrypted with the password authentication mode.
Use the build.sh script to build 3 executables:
- hash extractor
- BitCracker CUDA version
- BitCracker OpenCL version
For CUDA implementation, you need at least CUDA 7.5 and an NVIDIA GPU with minimum cc3.5 (i.e. Kepler arch)
The executables are stored in the build directory.
Before starting the attack, you need to run bitcracker_hash to extract the hash from the encrypted memory unit.
> ./build/bitcracker_hash -h
Usage: ./build/bitcracker_hash -i <Encrypted memory unit> -o <output file>
-h, --help Show this help -i, --image Path of memory unit encrypted with BitLocker -o, --outfile Output file
The extracted hash is fully compatible with the John The Ripper format.
Then you can use the output hash file to run the BitCracker attack.
> ./build/bitcracker_cuda -h Usage: ./build/bitcracker_cuda -f <hash_file> -d <dictionary_file> Options: -h, --help Show this help -f, --hashfile Path to your input hash file (HashExtractor output) -s, --strict Strict check (use only in case of false positives) -d, --dictionary Path to dictionary or alphabet file -g, --gpu GPU device number -t, --passthread Set the number of password per thread threads -b, --blocks Set the number of blocks
In case of false positives you can use the -s option, that is a more restrictive check on the correctness of the final result. Altough this check is empirically verified and it works with the images of this repo encrypted with Windows 7, 8.1 and 10, we can’t guarantee that it doesn’t lead to false negatives. Use -s option only if BitCracker returns several false positives.
In the run_test.sh script there are several attack examples using the encrypted images provided in this repo:
- imgWin7: memory unit encrypted with BitLocker using Windows 7 Enteprise edition OS
- imgWin8: memory unit encrypted with BitLocker using Windows 8 Enteprise edition OS
- imgWin10Compatible.vhd: memory unit encrypted with BitLocker (compatible mode) using Windows 10 Enteprise edition OS,
- imgWin10NonCompatible.vhd: memory unit encrypted with BitLocker (NON compatible mode) using Windows 10 Enteprise edition OS,
- imgWin10CompatibleLong27.vhd: memory unit encrypted with BitLocker (compatible mode) using Windows 10 Enteprise edition OS using the longest possible password (27 characters)
Currently, BitCracker is able to evaluate passwords having length between 8 (minimum password length) and 27 characters (implementation reasons).
BitCracker doesn’t provide any mask attack, cache mechanism or smart dictionary creation; therefore you need to provide your own input dictionary.