Embedded Device Audit

Supply-chain verification and integrity analysis for IoT devices, medical equipment, and industrial controllers. Detection of hardware backdoors, unauthorized components, and firmware tampering.

💰 Price Starting from €3,900

📅 Typical engagement 4–8 business days

🔒 Confidentiality NDA available

🔍 Investigation Methodology

🔹 Hardware teardown & component identification

🔹 PCB analysis & JTAG/UART enumeration

🔹 Firmware extraction & integrity verification

🔹 Supply-chain component traceability

🔹 Hidden debug interface detection

🔹 Backdoor / undocumented functionality analysis

🔹 Encryption & secure boot verification

📦 Supported devices: IoT sensors, medical devices (FDA class II/III), PLCs, industrial controllers, smart meters, automotive ECUs

📋 Example Investigation Scenario

Industrial PLC (Siemens S7-1200) – Supply-chain implant & hidden backdoor

🔧 1. Hardware Teardown & PCB Analysis

PLC main board – component inspection

JTAG header – debug interface

SPI flash – firmware extraction

📝 Finding: Unauthorized component detected – extra SPI flash chip not present in bill of materials.

🔌 2. Debug Interface Analysis (JTAG / UART)

$ openocd -f interface/jlink.cfg -f target/stm32f4x.cfg

Info : J-Link V9 compiled
Info : STM32F4xxx - Cortex-M4
Warning: Unknown device ID: 0x2BA01477

$ screen /dev/ttyUSB0 115200

U-Boot 2016.11 (Mar 12 2024 - 08:15:23)

[    1.234] Unknown command: 'factory_reset'
[    1.456] Debug shell enabled (password: maint2024)
[    1.567] Undocumented maintenance service initialized

Factory> (hidden debug shell)

🔍 Debug interface findings:
• Hidden debug shell – accessible via UART (password brute-forced)
• Unauthorized service (port 4444) – not in vendor documentation
• Modified U-Boot – additional commands added (factory_reset)
• JTAG device ID mismatch – suspicious component substitution

📀 3. Firmware Integrity Analysis

$ binwalk firmware.bin

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
0             0x0             U-Boot image (ARM Cortex-M)
131072        0x20000         Squashfs filesystem (version 4.0)
1572864       0x180000        RAW data (entropy 0.997)

$ strings suspicious_region.bin | head -10

telemetry_sync
factory_update
runtime_policy
process_sync
update.factory-service[.]com

$ diff vendor_firmware.bin suspect_firmware.bin

Binary files differ: 18792 bytes modified, 4096 bytes added at offset 0x180000

📝 Firmware findings:
• Extra encrypted region (23 KB) – not in vendor firmware
• Strings reveal industrial backdoor (telemetry_sync, process_sync)
• Hardcoded EC private key – likely for command authentication
• Suspicious domain: update.factory-service[.]com

🏭 4. Supply-Chain Component Verification

⚠️ Component Anomalies

• Extra SPI flash (Winbond) – not in BOM
• JTAG header populated – should be depopulated
• Unknown IC marking "X7G-42L" – not traceable
• PCB revision mismatch (v2.1 vs documented v2.0)

🔴 Tampering Indicators

• Solder residue on SPI flash (rework)
• Conformal coating irregularity
• Serial number sticker mismatch
• Security seal broken

✅ Verified Components

• Main MCU – authentic (STMicroelectronics)
• Power supply – matches BOM
• Crystal oscillators – genuine
• Passive components – within spec

🎯 Supply-Chain Attack Vector:

• Component substitution at contract manufacturer (extra SPI flash)
• Modified firmware flashed during production test
• Hidden debug interfaces left enabled
• Backdoor activates after 30 days of operation

💣 5. Vulnerability Assessment

CVE-2022-38465 CVSS 9.3 CRITICAL

Global Private Key Exposure

Offline attack against a single CPU can discover the private key of the entire CPU family.

→ Affects S7-1200 < V4.5.0

CVE-2019-13945 CVSS 6.8 MEDIUM

UART Diagnostic Mode Access

Manufacturing access mode via physical UART interface during boot process.

→ Physical access required

CVE-2024-47100 CVSS 7.1 HIGH

Cross-Site Request Forgery

CSRF vulnerability in web interface allows unauthorized actions.

→ Affects S7-1200 V4 < V4.7

🎯 Exploit Chain:

1. Physical UART access (CVE-2019-13945) → extracted firmware
2. CVE-2022-38465 → decrypted global private key
3. CVE-2024-47100 (CSRF) → chained with stolen credentials
4. Modified firmware deployed with backdoor

🏭 Operational Impact:

• Remote attacker could override PLC control logic
• Safety systems bypass – potential equipment damage
• Industrial espionage – process data exfiltration
• Ransomware vector – OT network compromise

⚠️ 6. Indicators of Compromise (IOC)

Hardware indicators:
- Extra SPI flash (Winbond 25Q16) – not in BOM
- JTAG header populated (J1)
- Unknown IC marking "X7G-42L"

Firmware indicators:
- SHA256 (vendor): 4e8c12a4f6b9d71e2c5a8b3f9e6d1c7a2b4f8e3d6c9a1b5e7f2d4c8a6b3e1f9d
- SHA256 (suspect): 7a2b4c6d8e0f2a4b6c8d0e2f4a6b8c0d2e4f6a8b0c2d4e6f8a0b2c4d6e8f0a2b
- Extra region at offset 0x180000

Network indicators:
- update.factory-service[.]com (185.130.5.254)
- Port 4444/tcp (unauthorized service)
- Beaconing pattern: every 60 seconds

Debug credentials:
- UART shell password: maint2024
- Hidden factory account: plc_service / Plc#2024

📄 Deliverables

📑 Full teardown report + photos

🔬 Firmware diff & binary analysis

🗺️ Supply-chain component traceability

⚠️ IOC list (hardware + software)

🛠️ Remediation roadmap

🏭 Manufacturing recommendations

⚠️ Not Included

❌ Source code review (unless provided) ❌ Device re-flashing or repair (optional extra) ❌ Functional safety certification (IEC 61508)

Ready to audit your embedded devices?

Submit a request or ask for a confidential quote. Starting from €3,900

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