Unauthorized modification of UEFI variables in UEFI systems

Overview

Certain firmware implementations may not correctly protect and validate information contained in certain UEFI variables. Exploitation of such vulnerabilities could potentially lead to bypass of security features and/or denial of service for the platform.

Description

As discussed in recent conference publications (CanSecWest 2014, Syscan 2014, and Hack-in-the-Box 2014) certain UEFI implementations do not correctly protect and validate information contained in the 'Setup' UEFI variable. On some systems, this variable can be overwritten using operating system APIs. Exploitation of this vulnerability could potentially lead to bypass of security features, such as secure boot, and/or denial of service for the platform. Please refer to the conference publications for further details.

Impact

A local attacker that obtains administrator access to the operating system may be able to modify UEFI variables. Exploitation of such vulnerabilities could potentially lead to bypass of security features and/or denial of service for the platform.

Solution

Contact your BIOS or system vendor to determine if your system is affected. Additionally, MITRE has released the open source Copernicus tool that can help determine if a particular BIOS image is affected.

Vendor Information (Learn More)

Vendor	Status	Date Notified	Date Updated
Dell Computer Corporation, Inc.	Affected	30 Aug 2013	09 Jun 2014
Intel Corporation	Affected	-	09 Jun 2014
American Megatrends Incorporated (AMI)	Unknown	-	09 Jun 2014
ASUSTeK Computer Inc.	Unknown	-	09 Jun 2014
Hewlett-Packard Company	Unknown	-	09 Jun 2014
Insyde Software Corporation	Unknown	-	09 Jun 2014
Lenovo	Unknown	-	09 Jun 2014
Phoenix Technologies Ltd.	Unknown	-	09 Jun 2014

If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group	Score	Vector
Base	6.0	AV:L/AC:H/Au:S/C:C/I:C/A:C
Temporal	4.7	E:POC/RL:OF/RC:C
Environmental	4.7	CDP:ND/TD:ND/CR:H/IR:H/AR:H

References

• https://security-center.intel.com/advisory.aspx?intelid=INTEL-SA-00038&languageid=en-fr
• http://haxpo.nl/hitb2014ams-kallenberg-cornwell-kovah-butterworth/

Credit

Thanks to Corey Kallenberg, Xeno Kovah, John Butterworth, and Sam Cornwell of the MITRE Corporation for reporting this vulnerability. Thanks also goes to the Advanced Threat Research and Security Center of Excellence from Intel.

This document was written by Todd Lewellen.

Other Information

• CVE IDs: CVE-2014-2961
• Date Public: 27 5월 2014
• Date First Published: 09 6월 2014
• Date Last Updated: 10 6월 2014
• Document Revision: 19