securing network equipment with trust and integrity

©2017 Trusted Computing Group

Securing Network Equipment

with Trust and Integrity


Agenda

• Threats to Network Equipment

• Locking Down Firmware

• Introduction to Trusted Computing

• Networking Applications for Trusted Computing

• References

• Call to Action

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THREATS TO NETWORK EQUIPMENT


The Threat

• Networked Equipment has become critical infrastructure

• Threats include

– Unauthorized devices that can gain access to networked data

– Unauthorized code that can interfere with safe operation

– Firmware implants that can render attacks invisible and unremovable

• E.g: Ukraine Power System Attack• Coordinated attacks on controllers, embedded gear and even the call center

• Some networking equipment permanently disabled

• https://www.wired.com/2016/03/inside-cunning-unprecedented-hack-ukraines-power-grid/

• http://www.nerc.com/pa/CI/ESISAC/Documents/E-ISAC_SANS_Ukraine_DUC_18Mar2016.pdf

• E.g. Dyn DNS Attack• Hundreds of thousands of IoT devices (including home routers) hijacked and added to

Mirai botnet to mount a DDoS attack on Dyn’s DNS servers, resulting in downtime

• https://en.wikipedia.org/wiki/2016_Dyn_cyberattack

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https://www.wired.com/2016/03/inside-cunning-unprecedented-hack-ukraines-power-grid/

http://www.nerc.com/pa/CI/ESISAC/Documents/E-ISAC_SANS_Ukraine_DUC_18Mar2016.pdf

https://en.wikipedia.org/wiki/2016_Dyn_cyberattack


Securing Infrastructure

• Today’s Scope: Embedded systems like routers, firewalls, switches, industrial controllers

• It’s important to consider security at all levels

– But particularly Firmware and Identity

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LOCKING DOWN FIRMWARE


Firmware Attacks

• Why so much focus on firmware attacks?

• It’s the first link in the chain of trust– If you skip a link in the chain, the remaining links cannot be trusted

• Firmware Hacks are usually persistent

– Firmware is not usually updated or examined

• Good for stealthy attacks!

– Hacks can be un-removable*

• The BIOS updates the BIOS– So if it doesn’t want to, it won’t

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*Without a hardware programmer


Securing Firmware

• Two Simple Steps:

• Make sure that the OS cannot modify firmware

– This usually needs some kind of hardware help to lock boot flash memory

• Make sure that the BIOS (or uBoot or whatever) won’t update itself without checking a signature on the new image.

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Secure Boot Defined

• Secure Boot(*) is a process that ensures that the device boots an unmodified, authorized image.

• Secure Boot is achieved by providing an unbroken “chain of trust” from the first instruction executed after Reset through to the OS prompt.

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Start BIOSInitialize hardwareCheck Loader Signature

Run LoaderLocate OS ImageCheck Kernel Signatures

KernelStart OS (eg Linux)Check and run Daemons

Core Root of Trust

BIOS checks Loader Signature before handoff

Loader checks Kernel

Signatures before handoff

*aka Verified Boot


INTRO TO TRUSTED COMPUTING


A trusted system is…predictable, even under stresstrusted based on experience and/or evidencebased on fundamental properties (identity, integrity)

What is a Trusted System?

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Trusted Platform Module:The Standard Hardware Root of Trust

• Trusted Platform Module (TPM)

– Self-contained security processor

– Inexpensive & small (~0.1 watt, ~$1)

– Connects to inexpensive processor buses

• TPM Provides:

– Secure storage of boot state (i.e. hashes of objects)

– Secure storage of cryptographic secrets (e.g. private keys)

– Cryptographic-quality Random Number Generator

– Includes resistance to physical attack, i.e., reverse-engineering, to keep private keys private

• Specified by Trusted Computing Group industry consortium

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TCG = Open Standards for Trusted Computing

• TCG is the only group focused on trusted computing standards

• You know TCG for our technical specs & guidance such as:– Trusted Platform Module (TPM 2.0)

– Self Encrypting Drive (SED)

– Trusted Network Connect (TNC)

• TPM specification implemented in more than a billion devices

– Chips integrated into PCs, servers, printers, kiosks, industrial systems, and many embedded systems


NETWORKING APPLICATIONS FOR TRUSTED COMPUTING


TCG Network Equipment Guidance

• TCG Guidance for Securing Network Equipment• Document developed by TCG members including many involved in

Networking– Juniper, Cisco, Huawei, HPE and others

• Intended to help equipment vendors useTCG technology to secure network infrastructure

• Includes Use Cases, Building Blocks, andImplementation Guidance

• Now in Public Review until September 11, 2017

https://trustedcomputinggroup.org/specifications-public-review

• Send feedback to [email protected]

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Applications for TPM in Networked Gear

• Cryptographic Random Number Generator• Unpredictable numbers are critical to secure cryptography

• Sealing Secrets• Keep VPN keys and other data-at-rest secure

• IEEE 802.1AR Cryptographic Device Identification• Use spoof-resistant cryptographic means to identity devices

• Software Attestation / Health-Check• Use records kept by the TPM to fingerprint each software module run

• … And many others

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Random Number Generator- Essential for Secure Protocols

• Protocols like IPsec, SSH, SSL and TLS use cryptographic keys

• Keys are often generated within the embedded device itself

• Keys are like passwords: if you can guess the key, you can break the protocol

• Cryptographic keys are typically generated from random numbers

• Without hardware help, computer algorithms can only generate Pseudo-Random sequences, not truly random numbers.

• Most TPMs contain a physical source of randomness (aka entropy) which can be used to generate reliable keys.

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Sealing Secrets

- Ensure that secrets remain secret!

• The TPM can be used to protect secrets like:

• VPN shared-secret keys

• Disk Encryption keys• Configure the TPM so it will only decrypt the secrets for use when the

platform is in a specified state, e.g.

• Known, unmodified OS

• And/or specific platform configuration

• And/or user password


IEEE802.1AR Device Identity

- Proves Which Device is Which

• Many embedded devices are ‘remote’ and difficult to protect or even identify reliably.

• The TPM can be configured with a unique cryptographic identifier based on device serial number

• Based on IEEE spec 802.1AR• Public Key Cryptography allows the device to assert its identity

• And then prove possession of a difficult-to-steal private key stored inside the TPM

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How Would a DevID be Used?

• Inventory – Ensure the devices you put in place are still there

• VPN login – Use DevID for remote login, so only authorized devices are allowed on your network

• Zero-Touch Configuration – Ensure that only authorized devices can call in to obtain configuration

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Attestation and Measured Boot - Proves What Software was Launched on your Device

• Secure Boot works well for deterministic early stages of boot

• But multi-core processors tend to be less predictable once the OS layer starts up

• The TPM can be used to record “measurements” of each executable run

• The TPM can then return those measurements to a management station later, signed by a key that only the TPM can know

• “Attestation” provides cryptographic assurance of which executables actually were run.

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REFERENCES


More Info

• TCG: www.trustedcomputinggroup.org

• NetEQ docs: http://trustedcomputinggroup.org/work-groups/embedded-systems/

• TPM docs: http://trustedcomputinggroup.org/work-groups/trusted-platform-module/

• https://trustedcomputinggroup.org/wp-content/uploads/TPM_Keys_for_Platform_Identity_v1_0_r3_Final.pdf

• http://forums.juniper.net/t5/Security-Now/What-is-a-Trusted-Platform-Module-TPM/ba-p/281128

• http://forums.juniper.net/t5/Security-Now/What-s-the-Difference-between-Secure-Boot-and-Measured-Boot/ba-p/281251

• TPM & secure boot:

– https://technet.microsoft.com/en-us/itpro/windows/keep-secure/tpm-recommendations

– https://msdn.microsoft.com/en-us/windows/hardware/commercialize/manufacture/desktop/secure-boot-overview

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http://www.trustedcomputinggroup.org/

http://trustedcomputinggroup.org/work-groups/embedded-systems/

http://trustedcomputinggroup.org/work-groups/trusted-platform-module/

https://trustedcomputinggroup.org/wp-content/uploads/TPM_Keys_for_Platform_Identity_v1_0_r3_Final.pdf

http://forums.juniper.net/t5/Security-Now/What-is-a-Trusted-Platform-Module-TPM/ba-p/281128

http://forums.juniper.net/t5/Security-Now/What-s-the-Difference-between-Secure-Boot-and-Measured-Boot/ba-p/281251

https://technet.microsoft.com/en-us/itpro/windows/keep-secure/tpm-recommendations

https://msdn.microsoft.com/en-us/windows/hardware/commercialize/manufacture/desktop/secure-boot-overview


CALL TO ACTION


What Can You Do?

• Lock down your firmware as described above

• Use a TPM to provide a cryptographic Random Number Generator

• Use TPM and DevID to identify embedded devices

• Provide feedback on NetEq Guidance until September 11, 2017


• Send feedback to [email protected]

• Join TCG to go deep into the topic

• Contribute to the work!

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http://www.trustedcomputinggroup.org/wp-content/uploads/NetEq-Synopsis_1_0r3.pdf

mailto:[email protected]


Thank You!

Questions?


Contacting Trusted Computing Group

[email protected]

LinkedIn Trusted Computing Group: https://www.linkedin.com/groups/4555624

Twitter: @TrustedComputin

YouTube channel: https://www.youtube.com/user/TCGadmin

BrightTalk webcasts (free): www.brighttalk.com, search “trusted computing” for library of demonstrations and presentations

http://www.trustedcomputinggroup.org/

mailto:[email protected]

https://www.youtube.com/user/TCGadmin

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