When Digital Forensics Reaches The Hardware Layer

Digital forensic investigations often depend on access to information stored on or processed by electronic devices. Depending on the case and the type of device involved, this may include files, communications, application data, transaction records, account information, or other evidence relevant to the investigation.

In many cases, this information can be acquired through the operating system, file system, backups, application data, or other accessible device interfaces. But modern devices increasingly use hardware-based security mechanisms that can prevent these approaches from reaching the information investigators need.

Secure boot, secure element, Trusted Execution Environment (TEE), encrypted storage, and other hardware-backed protections can restrict how a device starts, how access is authorized, and how protected information can be reached. When those protections become the barrier to an investigation, forensic teams may need to expand their methods beyond software-level acquisition and into hardware security testing.

When device security becomes the barrier

The challenge for forensic teams is not simply that devices are becoming more secure. It is that security controls are increasingly implemented in ways that can limit access to information required for an investigation.

A forensic team may have physical possession of a smartphone, cryptocurrency wallet, flash drive, or other electronic device but still be unable to reach the information stored on it.

The team may be able to identify the device and examine parts of its software environment, while access to the relevant data remains restricted by protections implemented elsewhere in the device.

Instead of only asking how to extract the information, the team also needs to understand what is preventing access to it. That may require identifying which part of the device controls access, how that protection is implemented, and whether there is a technically viable way to bypass it.

This is where hardware security knowledge becomes relevant to digital forensics.

Understanding what protects access to the device

Before selecting a test method, forensic specialists need to understand enough about the target device to identify where and how the relevant protection is implemented.

This does not necessarily require complete design documentation. In many forensic cases, source code, schematics, engineering documentation, or detailed information about the device architecture may not be available. The target may be seized, unfamiliar, proprietary, legacy, or specifically designed to resist unauthorized access.

Teams may therefore need to characterize the device directly. This can include identifying important hardware components, examining available interfaces, observing how the device behaves during security-sensitive operations, and determining which components are involved in controlling access.

The purpose of the characterization is not to analyze every part of the device. It is to identify the security mechanism that stands between the investigator and the information required for the case. Once that is understood, the team can make a more informed decision about whether further hardware-level investigation is justified and which method is appropriate.

Where hardware security testing fits into forensic analysis

Hardware security testing should support the forensic objective, not become the objective itself. The goal remains access to information that is relevant to the investigation.

Two methods that may be relevant are Side-Channel Analysis (SCA) and Fault Injection (FI).

Side-Channel Analysis measures physical signals produced while a device performs an operation. These measurements can provide information about internal activity that is not visible through normal software access.

Fault Injection applies a controlled disturbance while a device is operating to determine whether a specific security-sensitive operation can be influenced. For a forensic investigation, FI can be used to bypass a security feature and unlock a device without ever needing the password.

The method should follow from the device, the protection being investigated, and the information the forensic team is trying to reach. For both methods, there are different channels to consider, which include time, power, EM-emanation, and light. The choice of channel depends on the accessibility and the protection level. For instance, an analyst who wants to explore the type of cryptography, but does not want to make physical modifications, may want to use an EM probe to measure emanations that reveal the crypto algorithm and implementation. If an analyst wants to bypass a password verification, they may want to inject a well-timed voltage glitch by pushing a needle on a chip pin.

Keysight supports forensic labs with a variety of test tools and can provide a complete forensic lab, including training, to make challenging investigations successful. Our equipment has elaborate automation features that reduce manual work and allow for easy replication of results. Analysts trained on our test equipment achieve forensic breakthroughs by finding the missing puzzle pieces.

Deciding what capability to build internally

An organization that regularly receives protected smartphones, cryptocurrency wallets, embedded systems, custom electronics, or other strongly protected devices may have a stronger case for developing internal hardware security expertise.

For decision-makers, useful questions include:

• How often are investigations limited by an inability to access a protected device?
• Which types of devices create the greatest investigative challenges?
• What information are teams typically trying to obtain from those devices?
• Which capabilities already exist internally?
• Where are additional expertise, equipment, or training required?
• Which activities need to be performed in-house?
• Which specialist capabilities can be accessed externally when needed?

The objective is not to build the largest possible hardware laboratory. It is to ensure that the organization has an appropriate response when device security prevents investigators from reaching information required for a case.

Extending digital forensic capability

As device security becomes more sophisticated, forensic organizations may increasingly encounter cases where access to relevant information depends on understanding protections implemented below the software layer.

Forensic leaders therefore need to consider whether their teams can identify these cases, determine what is preventing access, and bring in the appropriate hardware security expertise when necessary.

The goal is straightforward: expand the range of protected devices that an organization can assess while maintaining controlled, technically justified, and repeatable forensic workflows.

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