Side-Channel Attacks & the Importance of Hardware-Based Security

The recent Meltdown and Spectre vulnerabilities found in CPUs are notable for many reasons and provide good lessons to everyone. These vulnerabilities exist in the CPU hardware and are a type of sophisticated attack known as a "side-channel attack." Discovered by hardware security experts, these attacks remind us that reliably evaluating the security of modern infrastructure requires a solid understanding of the hardware supporting that infrastructure.

Hardware-Based Security
Hundreds of billions of dollars have been spent on software-only malware detection, virus scanners, firewalls, and more, none of which detected these vulnerabilities. Software security tools will never be able to provide protection if the foundational hardware is insecure. Operating systems, hypervisors, and software security tools are not enough to keep applications secure. A new approach is needed that provides security from the hardware to the cloud.

As companies move to the public cloud, they face a shared responsibility model for security with the provider responsible for infrastructure security and the user responsible for application security. As organizations put workloads or data in the public cloud, it is often on shared infrastructure that is virtualized with multiple tenant virtual machines occupying the same system. Yet organizations are left with having little control over the risks of such a system.

One approach organizations can consider is to leverage trusted execution environments (TEEs) to run applications in a completely isolated execution environment called a secure enclave. Chances are you have used an Apple device with this approach — Touch ID and other sensitive data is all stored encrypted inside a secure enclave isolated from rest of the system. Technologies such as Intel SGX are the cloud equivalent of that. SGX enables applications to run in a completely isolated execution environment — a secure enclave. No other software component, not even those running with higher privilege levels, can access the enclave memory.

End-to-End Encryption
Encryption remains the most effective tool to protect data. Encrypted data is unintelligible even when disclosed. The mathematical nature of encryption trusts nothing. Mathematics is easy to analyze and hard to defeat. Encryption can most readily be deployed to secure data at rest. Tools such as PGP and BitLocker ensure that if someone steals your hard drive, the data remains protected. Similarly, encryption can be used to secure data in motion. Transport Layer Security (TLS) ensures that your communication with your favorite e-commerce website is protected from disclosure or modification.

Until recently, data in use was the window where data remained exposed, due to a lack of solutions for encryption of data in use. New technologies are emerging for protecting data in use or the application runtime. These runtime encryption solutions keep data encrypted even when held in the application's in-memory data structures, or when actively being used for computation. (Full disclosure: Fortanix delivers runtime encryption solutions; however, other solutions that leverage TEEs and provide data in use protection can also address this problem.)

By combining runtime encryption of data in use with TEEs such as Intel SGX, organizations can now perform secure computation on data in an untrusted environment, without exposing the data. By keeping data encrypted outside enclaves, runtime encryption reduces the scope of attacks because any attack that accesses data outside an enclave will get only encrypted data, which is unreadable without proper decryption keys. Even with a compromised system, hackers will not have access to sensitive data. In that way, runtime encryption would have protected applications against a Meltdown attack.

Responsibility of Technology Providers
The cloud and systems providers were very responsive in addressing the CPU vulnerabilities in a coordinated manner. Until the end of 2018, both Intel and Microsoft are running bug bounty programs focused specifically on side-channel vulnerabilities with a maximum reward of $250,000. Such collaboration between security researchers and vendors is designed to best protect customers.

Beyond the patching and the incentives, though, it is time to recognize the challenges inherent in cloud computing and accelerate innovation and adoption of technologies that enable new levels of isolation, privacy, and confidentiality between multiple tenants occupying the same system. Hardware chip providers have an important role to fuel the innovation with a hardware root of trust. Cloud providers need to be at the forefront in making these technologies available.

Finally, any innovation needs to focus on how to make these technologies easy to consume and have a minimal learning curve for application developers building agile cloud applications. Security should not become an inhibitor to the business, even when the stakes are this high.

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