|Main Archive Page > Month Archives > full-disclosure-uk archives|
-----BEGIN PGP SIGNED MESSAGE-----
Bitlocker is the disk encryption feature introduced in Microsoft Vista. It has the capability to authentify users in several way, including with a password (PIN), when configured to work with the TPM chip.
The password checking routine of Microsoft Bitlocker fails to sanitize the BIOS keyboard buffer after reading passwords, resulting in plain text password leakage to unprivileged local users.
Bitlocker's pre-boot authentication routines use the BIOS API to read user input via the keyboard. The BIOS internally copies the keystrokes in a RAM structure called the BIOS Keyboard buffer inside the BIOS Data Area. This buffer is not flushed after use, resulting in potential plain text password leakage once the OS is fully booted, assuming the attacker can read the password at physical memory location 0x40:0x1e.
Plain text password disclosure. Local guest access is required, but no physical access to the machine.
This vulnerability was discovered by Security Researcher Jonathan Brossard from iViZ Techno Solutions Pvt. Ltd.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (MingW32)
-----END PGP SIGNATURE-----