ISO/IEC 19678:2015
(Main)Information Technology — BIOS Protection Guidelines
Information Technology — BIOS Protection Guidelines
ISO 19678:2015 provides requirements and guidelines for preventing the unauthorized modification of Basic Input/Output System (BIOS) firmware on PC client systems. Unauthorized modification of BIOS firmware by malicious software constitutes a significant threat because of the BIOS's unique and privileged position within the PC architecture. A malicious BIOS modification could be part of a sophisticated, targeted attack on an organization ?either a permanent denial of service (if the BIOS is corrupted) or a persistent malware presence (if the BIOS is implanted with malware). As used in this publication, the term BIOS refers to conventional BIOS, Extensible Firmware Interface (EFI) BIOS, and Unified Extensible Firmware Interface (UEFI) BIOS. This International Standard applies to system BIOS firmware (e.g., conventional BIOS or UEFI BIOS) stored in the system flash memory of computer systems, including portions that may be formatted as Option ROMs. However, it does not apply to Option ROMs, UEFI drivers, and firmware stored elsewhere in a computer system. Subclause 7.2 provides platform vendors with requirements for a secure BIOS update process. Additionally, subclause 7.3 provides guidelines for managing the BIOS in an operational environment. While this International Standard focuses on current and future x86 and x64 client platforms, the controls and procedures are independent of any particular system design.
Technologies de l'information — Lignes directrices de protection BIOS
General Information
Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 19678
First edition
2015-05-01
Information Technology — BIOS
Protection Guidelines
Technologies de l’information — Lignes directrices de protection BIOS
Reference number
©
ISO/IEC 2015
© ISO/IEC 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO/IEC 2015 – All rights reserved
Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Conformance . 1
3 Normative references. 2
4 Terms and definitions . 2
5 Symbols (and abbreviated terms) . 3
6 Background . 4
6.1 System BIOS . 4
6.2 Role of System BIOS in the Boot Process . 5
6.3 Updating the System BIOS . 8
6.4 Importance of BIOS Integrity . 8
6.5 Threats to the System BIOS . 9
7 Threat Mitigation . 10
Bibliography . 14
© ISO/IEC 2015 – All rights reserved
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
Note: ITTF will provide the document number needed below
ISO/IEC 19678 was prepared by the U.S. National Institute of Standards and Technology from NIST SP 800-
147, BIOS Protection Guidelines. NIST SP 800-147 was reformatted in accordance with ISO/IEC Directives,
Part 2, while maintaining the technical content of the NIST publication (available at
http://csrc.nist.gov/publications/nistpubs/800-147/NIST-SP800-147-April2011.pdf). The resulting standard was
adopted under a special “fast-track procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information
technology, in parallel with its approval by the national bodies of ISO and IEC.
© ISO/IEC 2015 – All rights reserved
Introduction
Modern computers rely on fundamental system firmware, commonly known as the system Basic Input/Output
System (BIOS), to facilitate the hardware initialization process and transition control to the operating system.
The BIOS is typically developed by both original equipment manufacturers (OEMs) and independent BIOS
vendors, and is distributed to end-users by motherboard or computer manufacturers. Manufacturers
frequently update system firmware to fix bugs, patch vulnerabilities, and support new hardware. This
International Standard provides security requirements and guidance for preventing the unauthorized
modification of BIOS firmware on PC client systems.
Unauthorized modification of BIOS firmware by malicious software constitutes a significant threat because of
the BIOS’s unique and privileged position within the PC architecture. A malicious BIOS modification could be
part of a sophisticated, targeted attack on an organization—either a permanent denial of service (if the BIOS
is corrupted) or a persistent malware presence (if the BIOS is implanted with malware). The move from
conventional BIOS implementations to implementations based on the Unified Extensible Firmware Interface
(UEFI) may make it easier for malware to target the BIOS in a widespread fashion, as these BIOS
implementations are based on a common specification.
This International Standard focuses on current and future x86 and x64 desktop and laptop systems, although
the controls and procedures could potentially apply to any system design. Likewise, although the guide is
oriented toward enterprise-class platforms, the necessary technologies are expected to migrate to consumer-
grade systems over time. The security requirements do not attempt to prevent installation of unauthentic
BIOSs through the supply chain, by physical replacement of the BIOS chip, or through secure local update
procedures.
The intended audience for this International Standard includes BIOS and platform vendors, and information
system security professionals who are responsible for managing the endpoint platforms’ security, secure boot
processes, and hardware security modules. The material may also be of use when developing enterprise-
wide procurement strategies and deployment.
The material in this International Standard is technically oriented, and it is assumed that readers have at least
a basic understanding of system and network security. The International Standard provides background
information to help such readers understand the topics that are discussed. Readers are encouraged to take
advantage of other resources (including those listed in this International Standard) for more detailed
information.
© ISO/IEC 2015 – All rights reserved
Information Technology— BIOS Protection Guidelines
1 Scope
This International Standard provides requirements and guidelines for preventing the unauthorized
modification of Basic Input/Output System (BIOS) firmware on PC client systems. Unauthorized modification
of BIOS firmware by malicious software constitutes a significant threat because of the BIOS’s unique and
privileged position within the PC architecture. A malicious BIOS modification could be part of a
sophisticated, targeted attack on an organization —either a permanent denial of service (if the BIOS is
corrupted) or a persistent malware presence (if the BIOS is implanted with malware).
As used in this publication, the term BIOS refers to conventional BIOS, Extensible Firmware Interface (EFI)
BIOS, and Unified Extensible Firmware Interface (UEFI) BIOS. This International Standard applies to
system BIOS firmware (e.g., conventional BIOS or UEFI BIOS) stored in the system flash memory of
computer systems, including portions that may be formatted as Option ROMs. However, it does not apply to
Option ROMs, UEFI drivers, and firmware stored elsewhere in a computer system.
Subclause 7.2 provides platform vendors with requirements for a secure BIOS update process.
Additionally, subclause 7.3 provides guidelines for managing the BIOS in an operational environment.
While this International Standard focuses on current and future x86 and x64 client platforms, the controls
and procedures are independent of any particular system design.
2 Conformance
The following terms are used in this standard to indicate mandatory requirements, recommended options,
or permissible actions.
• The terms “shall” and “shall not” indicate requirements to be followed strictly in order to conform to
this standard and from which no deviation is permitted.
• The terms “should” and “should not” indicate that among several possibilities one is recommended
as particularly suitable, without mentioning or excluding others, or that a certain course of action is
preferred but not necessarily required, or that (in the negative form) a certain possibility or course of
action is discouraged but not prohibited.
• The terms “may” and “need not” indicate a course of action permissible within the limits of this
standard.
An implementation is conformant to this standard if it implements the requirements specified in subclause
7.2.
© ISO/IEC 2015 – All rights reserved
3 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
FIPS 186-4, Digital Signature Standard. July 2013.
NIST SP 800-89, Recommendation for Obtaining Assurances for Digital Signature Applications. November
2006.
NIST SP 800-131A, Transitions: Recommendation for Transitioning the Use of Cryptographic Algorithms
and Key Lengths. January 2011.
4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1
Basic Input/Output System (BIOS)
boot firmware, such as those based on the conventional BIOS, Extensible Firmware Interface (EFI), and the
Unified Extensible Firmware Interface (UEFI)
4.2
conventional BIOS
legacy boot firmware used in many x86-compatible computer systems (also known as the legacy BIOS)
4.3
Core Root of Trust for Measurement (CRTM)
the first piece of BIOS code that executes on the main processor during the boot process. On a system
with a Trusted Platform Module the CRTM is implicitly trusted to bootstrap the process of building a
measurement chain for subsequent attestation of other firmware and software that is executed on the
computer system.
4.4
Extensible Firmware Interface (EFI)
a specification for the interface between the operating system and the platform firmware. Version 1.10 of
the EFI specifications was the final version of the EFI specifications, and subsequent revisions made by the
Unified EFI Forum are part of the UEFI specifications
4.5
firmware
software that is included in read-only memory (ROM)
4.6
option ROM
firmware that is called by the system BIOS, such as BIOS firmware on add-on cards (e.g., video card, hard
drive controller, network card) as well as modules which extend the capabilities of the system BIOS
4.7
Protected Mode
an operational mode found in x86-compatible processors with hardware support for memory protection,
virtual memory, and multitasking
4.8
Real Mode
a legacy high-privilege operating mode in x86-compatible processors
2 © ISO/IEC 2015 – All rights reserved
4.9
System Management Mode (SMM)
a high-privilege operating mode found in x86-compatible processors used for low-level system management
functions
4.10
system flash memory
the non-volatile storage location of system BIOS, typically in electronically erasable programmable read-
only memory (EEPROM) flash memory on the motherboard. While system flash memory is a technology-
specific term, requirements and guidelines in this document referring to the system flash memory are
intended to apply to any non-volatile storage medium containing the system BIOS.
4.11
Trusted Platform Module (TPM)
a tamper-resistant integrated circuit built into some computer motherboards that can perform cryptographic
operations (including key generation) and protect small amounts of sensitive information, such as
passwords and cryptographic keys
4.12
Unified Extensible Firmware Interface (UEFI)
a specification for the interface between the operating system and the platform firmware developed by the
UEFI Forum
5 Symbols (and abbreviated terms)
ACPI
Advanced Configuration and Power Interface
BDS
Boot Device Selection
BIOS
Basic Input/Output System
CPU
Central Processing Unit
CRTM
Core Root of Trust for Measurement
DXE
Driver Execution Environment
EEPROM
Electrically Erasable Programmable Read-Only Memory
EFI
Extensible Firmware Interface
FIPS
Federal Information Processing Standard
GPT
GUID Partition Table
GUID
Globally Unique Identifier
© ISO/IEC 2015 – All rights reserved
----------------------
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.