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[ iViZ Security Advisory 08-004                            25/08/2008 ]
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iViZ Techno Solutions Pvt. Ltd.
                                            http://www.ivizsecurity.com
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* Title:     Intel BIOS Plain Text Password Disclosure
* Date:      25/08/2008
* Software:  Intel BIOS

* CERT temporary tracker : VU#604539

- --[ Synopsis:

    Like most BIOSes, Intel's firmware PE94510M.86A.0050.2007.0710.1559
    (07/10/2007) can be used to ask a password to users at boot time to
    implement a pre-boot authentication.

    The password checking routine of this firmware fails to sanitize the
    BIOS keyboard buffer after reading user input, resulting in plain
    text password leakage to local users.

- --[ Affected Software:

  * Intel Corp PE94510M.86A.0050.2007.0710.1559 (07/10/2007) 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

    http://www.ivizsecurity.com/research/preboot/preboot_whitepaper.pdf

- --[ Vendor response:

  * Intel Product Security Incident Response Team (iPSIRT)  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 July 15th 2008
  * CERT assigns tracker VU#604539 to the bug.
  * First Public disclosure at Defcon 16 on August 10th 2008

- --[ Reference:

    http://www.ivizsecurity.com/security-advisory.html


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