On this page
Published: February 23, 2024 · Last reviewed: May 1, 2026
Key Takeaways
- Hardware testing answers what an attacker with physical possession can achieve.
- Debug interfaces left active on production boards are the single most common finding.
- Firmware extraction from flash is straightforward without encryption at rest.
- Software defined radios let a tester observe a proprietary protocol without your app.
- Hardware findings often require board changes, so test before the design freezes.
- Testing must be authorized, documented, and performed on units you own or control.
Part of our Medical device vulnerability, threat, and attack-technique catalogue. For the full overview, start with The Top 50 Cybersecurity Issues with Medical Devices.
Hardware security testing of a medical device relies on a small, stable toolkit: a logic analyzer and USB-to-serial adapter for finding and using debug interfaces, a JTAG or SWD probe for processor access, a flash programmer for extracting firmware, a software defined radio for wireless analysis, and an oscilloscope and soldering equipment for physical work. Each tool answers a specific question about what an attacker with the device in hand can reach.
Reviewed September 17, 2026
Hardware testing exists because an attacker can buy your device. Once a physical unit is on a bench, the interfaces you left on the production board are available, the flash chip can be read, and the radio can be observed without your app in the way. None of that is visible to a software-only assessment.
This is a working overview of the tools used in authorized testing, what each one proves, and what the findings mean for your submission. It is written for manufacturers deciding what their testing should cover, not as instructions for unauthorized access.
Why Physical Attacks Belong in Your Threat Model
Medical devices are not kept in datacenters. They sit in clinic rooms, in patients' homes, in ambulances, and on resale sites. An attacker who wants to understand your device does not need to breach a hospital; they need to buy a used unit. Once they have one, they can spend unlimited time on it without anyone noticing, and anything they learn applies to every unit you shipped.
That last point is what makes hardware findings serious. A secret extracted from one device's flash is frequently a secret shared across the fleet, which converts a single physical compromise into a remote capability against every deployed unit. The February 3, 2026 premarket cybersecurity guidance expects the threat model to consider physical access, and reviewers ask about it when the architecture shows a device used outside a controlled environment.
The hardware layer is also where the most expensive findings live. A firmware bug is a build; an exposed debug interface on a production board may require a board revision, and board revisions have lead times measured in months.
The Core Toolkit and What Each Tool Proves
| Tool | What it does | What a finding means |
|---|---|---|
| Logic analyzer | Captures digital signals on board traces and test points | Identifies live UART, SPI, or I2C interfaces on the production board |
| USB-to-serial adapter | Connects to a UART console | Reveals boot logs, shells, or an unauthenticated console |
| JTAG or SWD probe | Debug access to the processor | Halt, single-step, read memory, sometimes bypass protections |
| Flash programmer or reader | Reads memory chips directly, in place or removed | Firmware and stored secrets recoverable without encryption at rest |
| Software defined radio | Receives and transmits arbitrary radio protocols | Proprietary protocols can be observed, replayed, or spoofed |
| Bluetooth and Wi-Fi test radios | Protocol-level wireless testing | Pairing, reconnection, and authorization weaknesses |
| Oscilloscope | Analog signal analysis | Timing behavior, glitch susceptibility, side-channel indicators |
| Soldering and rework station | Attaches probes, removes chips | Enables the access the other tools require |
| Microscope | Board inspection and fine rework | Identifies test points and chip markings |
| Bench power supply | Controlled power delivery | Supports fault injection and brownout behavior testing |
The logic analyzer and serial adapter combination produces more findings than anything else on the list, because unpopulated headers and test pads are routinely left connected on production boards. They were needed for development, nobody disabled them for production, and they frequently drop the tester into a root shell.
[KEY REQUIREMENT] Confirm, in writing, what your production boards expose. The answer should come from testing a production unit, not from reviewing the design intent, because the two often differ.
What Hardware Testing Typically Finds
| Finding | How it is discovered | Consequence |
|---|---|---|
| Active UART console | Logic analyzer plus serial adapter | Boot logs, configuration, sometimes an unauthenticated shell |
| Enabled JTAG or SWD | Probe attached to test points | Memory read and write, debug control of the processor |
| Unencrypted firmware in flash | Flash reader, in place or after chip removal | Full firmware for offline analysis; credentials and keys |
| Hardcoded or shared secrets | Firmware analysis after extraction | A fleet-wide compromise from one physical unit |
| No secure boot | Modified firmware flashed back and executed | Persistent attacker-controlled code on the device |
| Unauthenticated update acceptance | Crafted image applied over the update path | Remote compromise if the same path is network reachable |
| Proprietary radio without authentication | SDR capture and replay | Commands accepted from an unauthorized transmitter |
| Glitch-susceptible boot | Controlled power or clock disturbance | Security checks bypassed during startup |
The chain from an extracted firmware image to a shared secret to a remote attack is the pattern that turns a hardware finding into a submission-level problem. It is also the reason reviewers treat "an attacker would need physical access" as a weaker mitigation argument than manufacturers expect.
What Hardware Testing Does Not Tell You
Hardware testing has limits worth stating so the scope is honest. It does not evaluate your cloud services, it does not assess your mobile application's logic, and it does not substitute for source code review. It also produces destructive outcomes sometimes, which is why testers ask for multiple units.
It is also not, on its own, proof that your security requirements were implemented. A test that fails to extract firmware on a given day shows that this tester, in this time budget, with this equipment, did not succeed. Verifying that your documented controls exist and function is a separate activity, and both belong in the evidence package.
Doing This Legally and Safely
See also: Medical Device Abuse & Misuse Testing, Medical Device Closed Box Testing, and Medical Device Vulnerability Testing.
Every technique here is legitimate on equipment you own or are authorized to test, and problematic otherwise. Authorized testing has a written agreement that names the devices, the permitted techniques, and the disclosure path for findings. Testing is performed on units removed from clinical use, on an isolated bench, with radio work conducted so as not to interfere with equipment in use nearby.
Findings involving third-party components follow coordinated disclosure to the component vendor, and findings in fielded devices follow your vulnerability disclosure process. If your product incorporates a chipset with a known advisory history, your SBOM is what tells you which of your units are affected.
How Blue Goat Cyber Approaches This
We test hardware because that is where the assumptions break. Our lab work covers debug interface discovery, firmware extraction and analysis, secure boot verification, radio protocol analysis, and fault injection where the threat model justifies it, with findings written against the harm they enable rather than against a generic severity scale.
Hardware work is part of our medical device penetration testing, and the physical attack paths it surfaces feed back into the threat modeling that determines what your architecture views need to show.
Frequently Asked Questions
Why does hardware testing matter if the device is inside a hospital?
Because devices leave controlled environments routinely, through home use, resale, theft, loss, and service returns. A single unit on an attacker's bench yields firmware, secrets, and protocol knowledge that apply to every device you shipped. Physical access is also unsupervised access, which means an attacker can work for weeks without triggering any detection.
What is the most common hardware finding in medical devices?
An active debug interface on a production board, usually UART or JTAG. It survives because it was needed during development and nobody disabled it for production, and it frequently provides console or memory access without authentication. It is also the finding most likely to require a board change, which is why hardware testing belongs before the design freezes.
Can firmware be extracted if the debug ports are disabled?
Often, yes. Flash memory can be read directly, either in place or after removing the chip, unless the firmware is encrypted at rest and the key is held in protected storage. Disabling debug ports raises the effort required but does not by itself protect the contents of an external flash chip.
Does encrypting firmware solve the problem?
It raises the bar considerably, but only if the key is protected. Encryption with a key stored in the same accessible flash, or shared identically across the fleet, provides much less protection than it appears to. The strength comes from hardware-backed key storage and per-device keys, which are decisions made during silicon and board design.
Is fault injection testing necessary for every device?
No. It is justified when the threat model includes a motivated attacker with physical possession and when a bypassed boot check would have serious consequences, which is common for implantables, controlled substance delivery, and devices holding fleet-wide secrets. For lower-risk devices, debug interface and firmware extraction testing usually covers the realistic threat.
How many units should we provide for hardware testing?
At least two, and more if chip removal is anticipated. Hardware testing damages units, and a test that ends because the only available device stopped working produces an incomplete report. Providing spares is cheaper than repeating the engagement.
Find Out What Your Board Exposes
If nobody has put your production hardware on a bench, you do not yet know what an attacker who buys one will find. We can tell you while a board change is still affordable. Book a strategy session.
Blue Goat Cyber specializes in medical device cybersecurity, from threat modeling and penetration testing through premarket submission support. Our team works exclusively with device manufacturers preparing FDA submissions. Learn more about Christian Espinosa, our founder and CEO.
About the author
Christian Espinosa, MBA, CISSP · Founder & CEO, Blue Goat Cyber
U.S. Air Force Academy graduate and veteran with 30+ years in cybersecurity. Founded Alpine Security in 2014 (acquired 2020), then Blue Goat Cyber in 2022. Has supported 275+ FDA medical device submissions; no client has failed to clear due to cybersecurity. Author of three books including The Smartest Person in the Room. Ironman triathlete and mountaineer.
