GIGABYTE BRIX UEFI firmware fails to implement write protection and is not cryptographically signed

Overview

GIGABYTE BRIX UEFI firmware for the GB-BSi7H-6500 and GB-BXi7-5775 platforms, versions vF6 and vF2 respectively, fails to properly set the BIOSWE, BLE, SMM_BWP, and PRx bits to enforce write protection. It also is not cryptographically signed. These issues may permit an attacker to write arbitrary code to the platform firmware, potentially allowing for persistent firmware level rootkits or the creation of a permanent denial of service condition in the platform.

Description

CWE-693: Protection Mechanism Failure - CVE-2017-3197

GIGABYTE UEFI firmware for the GB-BSi7H-6500 and GB-BXi7-5775 platforms fails to properly set the BIOSWE, BLE, SMM_BWP, and PRx bits. As a result, the BIOS is not protected from arbitrary write access and may permit modifications to the SPI flash.

CWE-345: Insufficient Verification of Data Authenticity - CVE-2017-3198

GIGABYTE UEFI firmware for the GB-BSi7H-6500 and GB-BXi7-5775 platforms is not cryptographically signed and is served over HTTP from the vendor’s support pages without a checksum. An attacker in the position to do so may introduce arbitrary modifications to the firmware that the system has no means to detect.

Note that the affected GIGABYTE firmware is a vulnerable implementation of an AMI reference design that does not, by default, appear to be affected by these issues. For more information about these findings, refer to the Cylance advisories, CLVA-2017-01-001 and CLVA-2017-01-002.

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Impact

A local, authenticated attacker may be able to execute arbitrary code with the privileges of system firmware, potentially allowing for persistent firmware level rootkits or the creation of a permanent denial of service condition in the platform.

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Solution

The vendor has indicated that firmware version F7 for the GB-BSi7H-6500 will be released in April to address these issues. Users should monitor the product page or contact the vendor for update availability.

The vendor has indicated that the GB-BXi7-5775 is end of life and will not receive new firmware.

The CERT/CC is currently unaware of a practical solution for these problems.

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Vendor Information

507496

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GIGABYTE __ Affected

Notified: January 24, 2017 Updated: March 22, 2017

Status

Affected

Vendor Statement

We have not received a statement from the vendor.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.

Addendum

GB-BSi7H-6500 and GB-BXi7-5775 platforms, versions vF6 and vF2 respectively, are affected.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23507496 Feedback>).

CVSS Metrics

Group	Score	Vector
Base	6	AV:L/AC:H/Au:S/C:C/I:C/A:C
Temporal	5.1	E:POC/RL:ND/RC:UR
Environmental	7.1	CDP:MH/TD:ND/CR:ND/IR:H/AR:ND

References

• <https://cwe.mitre.org/data/definitions/693.html&gt;
• <https://cwe.mitre.org/data/definitions/353.html&gt;
• <http://www.gigabyte.us/Mini-PcBarebone/GB-BSi7H-6500-rev-10&gt;
• <http://www.gigabyte.us/Mini-PcBarebone/GB-BXi7-5775-rev-10&gt;
• <https://github.com/CylanceVulnResearch/disclosures/blob/master/CLVA-2017-01-001.md&gt;
• <https://github.com/CylanceVulnResearch/disclosures/blob/master/CLVA-2017-01-002.md&gt;

Acknowledgements

Thanks to Alex Matrosov of Cylance for reporting these vulnerabilities.

This document was written by Joel Land.

Other Information

CVE IDs:	CVE-2017-3197, CVE-2017-3198
Date Public:	2017-03-31 Date First Published: