Built into virtually every hardware device, firmware is lower-level software that is programmed to ensure that hardware functions properly.
As software security has been significantly hardened over the past two decades, hackers have responded by moving down the stack to focus on firmware entry points. Firmware offers a target that basic security controls can’t access or scan as easily as software, while allowing them to persist and continue leveraging many of their tried and true attack techniques.
The industry has reacted to this shift in attackers’ focus by making advancements in firmware security solutions and best practices over the past decade. That said, many organizations are still suffering from firmware security blind spots that prevent them from adequately protecting systems and data.
This can be caused by a variety of factors, from simple platform misconfigurations or reluctance about installing new updates to a general lack of awareness about the imperative need for firmware security.
In short, many don’t know what firmware security hazards exist today. To help readers stay more informed, here are three firmware security blind spots every organization should consider addressing to improve its overall security stance:
1. Firmware security awareness
The security of firmware running on the devices we use every day has been a novel focus point for researchers across the security community. With multiple components running a variety of different firmware, it might be overwhelming to know where to start. A good first step is recognizing firmware as an asset in your organization’s threat model and establishing the security objectives towards confidentiality, integrity, and availability (CIA). Here are some examples of how CIA applies to firmware security:
Confidentiality: There may be secrets in firmware that require protection. The BIOS password, for instance, might grant attackers authentication bypass if they were able to access firmware contents.
Integrity: This means ensuring the firmware running on a system is the firmware intended to be running and hasn’t been corrupted or modified. Features such as secure boot and hardware roots of trust support the measurement and verification of the firmware you’re running.
Availability: In most cases, ensuring devices have access to their firmware in order to operate normally is the top priority for an organization as far as firmware is concerned. A potential breach of this security objective would come in the form of a permanent denial of service (PDoS) attack, which would require manual re-flashing of system components (a sometimes costly and cumbersome solution).
The first step toward firmware security is awareness of its importance as an asset to an organization’s threat model, along with the definition of CIA objectives.
2. Firmware updates
The increase in low-level security research has led to an equivalent increase in findings and fixes provided by vendors, contributing to the gradual improvement of platform resilience. Vendors often work with researchers through their bug bounty programs, their in-house research teams, and with researchers presenting their work in conferences around the world, in order to conduct coordinated disclosure of firmware security vulnerabilities. The industry has come a long way enabling collaboration, enabling processes and accelerating response times towards a common goal: improving the overall health and resilience of computer systems.
The firmware update process can be complex and time consuming, and involves a variety of parties: researchers, device manufacturers, OEM’s, etc. For example, once UEFI’s EDK II source code has been updated with a new fix, vendors must adopt it and push the changes out to end customers. Vendors issue firmware updates for a variety of reasons, but some of the most important patches are designed explicitly to address newly discovered security vulnerabilities.
Regular firmware updates are vital to a strong security posture, but many organizations are hesitant to introduce new patches due to a range of factors. Whether it’s concerns over the potential time or cost involved, or fear of platform bricking potential, there are a variety of reasons why updates are left uninstalled. Delaying or forgoing available fixes, however, increases the amount of time your organization may be at risk.
A good example of this is WannaCry. Although Microsoft had previously released updates to address the exploit, the WannaCry ransomware wreaked havoc on hundreds of thousands of unpatched computers throughout the spring of 2017, affecting hundreds of countries and causing billions of dollars in damages. While this outbreak wasn’t the result of a firmware vulnerability specifically, it offers a stark illustration of what can happen when organizations choose not to apply patches for known threats.
Installing firmware updates regularly is arguably one of the most simple and powerful steps you can take toward better security today. Without them, your organization will be at greater risk of sustaining a security incident, unaware of fixes for known vulnerabilities.
If you’re concerned that installing firmware updates might inadvertently break your organization’s systems, consider conducting field tests on a small batch of systems before rolling them out company-wide and remember to always have a backup of the current image of your platform to revert back to as a precautionary measure. Be sure to establish a firmware update cadence that works for your organization in order to keep your systems up to date with current firmware protections at minimal risk.
3. Platform misconfigurations
Another issue that can cause firmware security risks is platform misconfigurations. Once powered on, a platform follows a complex set of steps to properly configure the computer for runtime operations. There are many time- and sequence-based elements and expectations for how firmware and hardware interact during this process, and security assumptions can be broken if the platform isn’t set up properly.
Disabled security features such as secure boot, VT-d, port protections (like Thunderbolt), execution prevention, and more are examples of potentially costly platform misconfigurations. All sorts of firmware security risks can arise if an engineer forgets a key configuration step or fails to properly configure one of the hundreds of bits involved.
Most platform misconfigurations are difficult to detect without automated security validation tools because different generations of platforms may have registers defined differently, there are a long list of things to check for, and there might be dependencies between the settings. It can quickly become cumbersome to keep track of proper platform configurations in a cumulative way.
Fortunately, tools like the Intel-led, open-source Chipsec project can scan for configuration anomalies within your platform and evaluate security-sensitive bits within your firmware to identify misconfigurations automatically. As a truly cumulative, open-source tool, Chipsec is updated regularly with the most recent threat insights so organizations everywhere can benefit from an ever-growing body of industry research. Chipsec also has the ability to automatically detect the platform being run in order to set register definitions. On top of scanning, it also offers several firmware security tools including fuzzing, manual testing, and forensic analysis.
Although there are a few solutions with the capability to inspect a systems’ configuration, running a Chipsec scan is a free and quick way to ensure a particular system’s settings are set to recommended values.
Your organization runs on numerous hardware devices, each with its own collection of firmware. As attackers continue to set their sights further down the stack in 2020 and beyond, firmware security will be an important focus for every organization. Ensure your organization properly prioritizes defenses for this growing threat vector, install firmware updates regularly, commit to continuously detect potential platform misconfigurations, and enable available security features and their respective policies in order to harden firmware resiliency towards confidentiality, integrity and availability.