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Security AdvisoriesLenovo BIOS Plain Text Password DisclosureSynopsisLike most BIOSes, Lenovo's firmware 7CETB5WW v2.05 (10/13/2006) 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 SoftwareLenovo 7CETB5WW v2.05 (10/13/2006) BIOS (possibly others too)Technical DescriptionThe 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.ImpactPlain 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 WhitepaperTechnical WhitepaperPatch DescriptionRead the detailed fix descriptionVendor ResponseIntel Product Security Incident Response Team (iPSIRT) has acknowledged the vulnerability and is proactively working on a fix.CreditsThis vulnerability was discovered by Security Researcher Jonathan Brossard from iViZ Techno Solutions Pvt. Ltd.Disclosure TimelineFirst private disclosure to vendor on July 15th 2008
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