Security Advisories
Hewlett-Packard BIOS Plain Text Password Disclosure
Synopsis
Like most BIOSes, HP 68DTT Ver. F.0D can be used to ask a password
to users at boot time to implement a pre-boot authentication.
The password checking routine of Hewlett-Packard 68DTT Ver. F.0D
(11/22/2005) fails to sanitize the BIOS keyboard buffer after reading
user input, resulting in plain text password leakage to local users.
Affected Software
Hewlett-Packard 68DTT Ver. F.0D BIOS (possibly others too)
Technical Description
The BIOS'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.
Impact
Plain text password disclosure. Local access is required, but no
physical access to the machine. The level of privilege required to retrieve the password from memory
is OS dependant and varies from guest user under Microsoft Windows
(any) to root user under most Unix based OSes.
Full Technical Whitepaper
Patch Description
Vendor Response
HP Software Security Response Team has aknowledged the vulnerability and
is proactively working on a fix.
Credits
This vulnerability was discovered by Security Researcher
Jonathan Brossard from iViZ Techno Solutions Pvt. Ltd.
Disclosure Timeline
First private disclosure to vendor on July 15th 2008
First vendor reply on 1st August 2008, assigned vendor
tracker SSRT080104.
First Public disclosure at Defcon 16 on August 10th 2008
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