Security Highlight: When Lasers Enter the Threat Model for TROPIC01

Secure elements are designed to protect sensitive assets even in exposed or hostile environments. But strong protection requires more than state-of-the-art cryptography — the implementation must also remain robust when an attacker has physical access to the device and can interact directly with the hardware.

A recent security advisory from Tropic Square highlights this challenge. It describes a potential bypass of firmware verification in the TROPIC01 secure element using Laser Fault Injection (LFI) that was discovered by Ledger’s Donjon. The vulnerability, rated Medium severity (CVSS 3.1 score: 5.7), targets the signature verification procedure during firmware loading. If successfully exploited, an attacker could execute unauthorized application firmware on the chip.

The attack is non-trivial. It requires full physical access, including desoldering and decapsulation, as well as expert-level hardware security skills and specialized LFI equipment. Tropic Square estimates a laboratory setup cost exceeding €30,000, with an exploitation effort of 3-4 weeks for a skilled attacker.

While complex, this type of attack highlights a crucial security engineering concept: threat modeling. Even advanced physical attacks can become relevant when devices protect high-value assets such as cryptographic keys, credentials, payment data, or identity information. Tropic Square’s transparent, detailed disclosure is uncommon in the secure element space and sets a strong example for the industry.

Firmware verification under fault conditions

Firmware verification is a critical security boundary. It ensures that only authenticated and authorized code can be executed by the device. If this boundary is weakened, all higher-level protections that depend on it are potentially exposed.

The reported attack specifically targets this boundary. By inducing a precisely timed fault, an attacker may disrupt the signature verification flow, effectively causing the device to skip or mis-evaluate part of the validation process.

This is exactly what fault injection testing is designed to assess: whether an attacker can influence execution at the right moment to alter a security decision.

A lab-grade attack, but still a relevant security risk

The reported laser fault injection attack is technically demanding, requiring invasive chip preparation, advanced tooling, and significant expertise. The unauthorized firmware is also non-persistent, meaning the attacker must repeat the manipulation on each power cycle.

These constraints reduce the likelihood of opportunistic exploitation — but they do not make the issue irrelevant.

In high-value contexts, attackers may be willing to invest considerable time and resources. Once an attack path is understood and optimized, repeating it across additional devices can become faster and more efficient. This is why hardware security evaluations remain critical for products that protect long-term secrets or operate in regulated markets.

Examples include:

• Payment and banking systems – where secure elements protect transaction credentials and cryptographic keys
• Identity and access control – such as eIDs, authentication tokens, and secure login devices
• Automotive systems – where embedded security components protect firmware integrity, vehicle access, diagnostics, OTA updates, and inter-ECU communication over long lifecycles
• Industrial IoT and critical infrastructure – where devices may be physically accessible and protect credentials tied to larger operational systems

Ultimately, any product protecting valuable digital assets can become a target if the value of those assets outweighs the cost of a sophisticated lab-based attack.

Automotive systems provide a good example of a hostile, high-stakes environment. Components from vehicles may be accessible through supply chains, repair environments, aftermarket sources, or dismantled vehicles, allowing attackers to analyze them in a lab before applying the results more broadly. As the EU Chips Act aims to strengthen Europe’s trusted semiconductor ecosystem, security-critical automotive applications face important requirement: chips must be robust against advanced physical attacks to remain secure throughout their expected lifecycle.

Risk depends on the application threat model

The same vulnerability can have very different implications depending on how and where a device is deployed. A device in a tightly controlled environment with strong physical protections may face limited exposure. A device deployed in the field, accessible to attackers over time, or protecting high-value assets may require deeper scrutiny.

For security teams, this means looking beyond the CVSS score and evaluating real-world impact. Key questions include:

• Does an attacker have realistic physical access to the device?
• What assets are protected by the secure element?
• Would compromising one device affect only that unit — or a wider ecosystem?
• How are firmware updates managed and secured?
• Are maintenance or debug modes restricted in production?
• Has secure boot and firmware verification been evaluated under fault conditions?

Tropic Square recommends several mitigations for current devices, including strengthening physical security controls, restricting maintenance modes, and ensuring firmware updates are performed in secure environments. Future versions are expected to incorporate additional bootloader and silicon-level protections.

Conclusion

The level of security testing should align with the value of the assets being protected. Not every product requires invasive evaluation, but devices that safeguard keys, credentials, financial assets, identity data, or long-term secrets should be assessed against realistic physical attack scenarios.

As embedded systems increasingly protect critical and high-value assets, advanced hardware security testing becomes essential. It provides the evidence needed to understand real-world risk, strengthen implementations, and support long-term trust across the product lifecycle.

To learn more about building a device security test lab for evaluating hardware and embedded product security, visit:
https://www.keysight.com/us/en/cmp/build-your-device-security-test-lab.html

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