The latest security information on Intel® products.

DCI Policy Update

Intel ID:
 INTEL-SA-00127
Product family:
 5th and 6th generation Intel® Xeon® Processor E3 family, Intel® Xeon® Scalable processors, and Intel® Xeon® Processor D family
Impact of vulnerability:
 Information Disclosure, Escalation of Privilege
Severity rating:
 Important
Original release:
 07/09/2018
Last revised:
 07/09/2018
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Summary:

Intel is releasing Direct Connect Interface (DCI) policy update.

Description:

Existing UEFI setting restrictions for DCI (Direct Connect Interface) in 5th and 6th generation Intel® Xeon® Processor E3 Family, Intel® Xeon® Scalable processors, and Intel® Xeon® Processor D Family can potentially allow a limited physical presence attacker to access platform secrets via debug interfaces.

Affected products:

•    Note:  Client platforms are not included in the following table, because all client platforms are expected to have EFI Secure Boot enabled & the UEFI Variable controlling DCI set to default disabled.

Potentially Affected Platform

Mitigated Platform sample code

Code Name Purley:

Intel® Xeon® Scalable processors

Available in Post Launch Release 7

or later on VIP @ https://platformsw.intel.com

Code Name Greenlow:

Intel® Xeon® Processor E3 v6 Family (Kaby Lake)

Intel® Xeon® Processor E3 v5 Family (Skylake)

Perform a code review based on TA content and remove the vulnerability as necessary. 

Code Name Bakerville:

Intel® Xeon® Processor D Family (Skylake-D)

Available in Post Launch Release 2

or later on VIP @ https://platformsw.intel.com

Code Name Harrisonville:

Intel® Atom ™ Processor C Series (Denverton)

Perform a code review based on TA content and remove the vulnerability as necessary. 

 

Recommendations:

Intel highly recommends that all potentially affected platforms modify the DCI policy such that DCI control is disabled.  Below are references to Purley, Bakerville, and Greenlow codebases.

•    Sample Code Filename:

        Greenlow filename:  PeiPchPolicyDebugLib.c

        Purley/Bakerville filename:  PeiPchPolicyUpdate.c

•    Code to change in Sample Code File:

        PchPolicy->DciConfig.DciEn  = 0;

        PchPolicy->DciConfig.DciAutoDetect = 0;

Acknowledgements:

Intel would like to thank Jesse Michael from Eclypsium for reporting this issue and working with us on coordinated disclosure.

Revision History

Revision Date Description
1.0 07/09/2018 Initial Release
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CVE Name: CVE-2018-3652

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