Most medical device manufacturers understand the risk of malware, ransomware, or unsecured APIs—but a more insidious threat often flies under the radar: steganography. Unlike traditional exploits, steganography doesn’t break into systems overtly. Instead, it hides malicious code or data inside normal-looking files or transmissions, making detection extremely difficult.
In this post, we explore how attackers could use steganography to infiltrate connected medical devices, compromise patient safety, and evade traditional security controls—and what manufacturers can do to stay ahead.
What Is Steganography in Cybersecurity?
Steganography is the practice of hiding information inside other non-suspicious data. While encryption disguises content, steganography disguises the presence of content itself.
📦 Common Steganographic Techniques:
- Embedding code in image files (e.g., PNG, JPEG, DICOM)
- Hiding payloads in audio, video, or waveform files
- Inserting commands or identifiers in metadata fields
- Concealing scripts in firmware update binaries
In the context of medical devices, these techniques can be used to:
- Inject backdoors during firmware updates
- Steal protected health information (PHI) without triggering alerts
- Alter or spoof telemetry data
How Steganography Targets Medical Devices
Connected medical devices are ideal targets due to their:
- Regular use of firmware and software updates
- Constant streaming of patient telemetry
- Integration with imaging systems and PACS
- API-driven cloud reporting systems
Let’s examine specific attack vectors:
🛠️ Firmware Modification
Attackers embed hidden instructions in firmware binaries. Since these updates often bypass deep inspection, malicious code can reside undetected for long periods.
Example: A rogue update file for a surgical robot contains a few extra kilobytes—hiding a beacon that connects the device to a command-and-control server.
📤 Data Exfiltration via Telemetry or Imaging
Data embedded in standard device telemetry, such as waveform packets, or inside diagnostic imaging files (DICOM), allows attackers to smuggle patient data past monitoring systems.
Example: A compromised device encodes stolen patient info inside image metadata and uploads it to a legitimate PACS.
🕳️ Hidden Command Channels
Attackers may encode signals in wireless transmissions or telemetry headers. These covert commands can trigger specific behaviors (e.g., deactivate alerts, delay logs) without detection.
Example: An attacker sends a subtle variation in Bluetooth signal patterns to activate hidden routines in a cloned device.
Detection & Defense: How to Secure Your Devices
🔎 Detection Strategies
- Use binary comparison tools to analyze firmware for hidden bytecode
- Monitor image, telemetry, and metadata anomalies
- Employ machine learning models to flag abnormal packet patterns
🛡️ Defense Mechanisms
- Sign and hash all firmware and update packages
- Implement secure boot and run-time integrity checks
- Limit metadata exposure and sanitize inputs/outputs
- Include covert channel and cloning simulation in your pen testing
FDA Compliance: Why It Matters
The FDA’s 2025 Cybersecurity Guidance requires manufacturers to:
- Address integrity and authenticity of all software and communication pathways
- Include supply chain verification of firmware and software
- Validate defenses in the Secure Product Development Framework (SPDF)
If you fail to account for steganographic or covert channel risks in your threat modeling, SBOM, or cybersecurity documentation, your submission could face deficiencies or postmarket scrutiny.
FAQs
Q: Is steganography used in real attacks today?
A: Yes. Nation-state actors and cybercriminals use steganography in espionage and APTs. Healthcare is a top target.
Q: What devices are most at risk?
A: Devices with OTA updates, telemetry, or cloud-linked diagnostics—such as monitors, insulin pumps, or imaging hardware.
Q: Can these threats be detected in regulatory testing?
A: Only if explicitly tested for. Standard scans and validations often overlook hidden payloads unless steganography is included in test plans.
Final Thoughts
Medical devices face increasingly sophisticated attacks—and steganography is one of the most difficult to detect. If your device can receive updates, send data, or interact with cloud services, it may already be a target.
Addressing this threat isn’t optional. It’s essential for protecting patients, meeting FDA expectations, and building lasting trust in your product.
Blue Goat Cyber: Pen Testing for the Hidden Threats Others Miss
We simulate advanced attack vectors—including steganography and covert channels—as part of our medical device cybersecurity assessments. Whether you’re preparing an FDA submission or hardening your postmarket defenses, we help you uncover what’s hidden.