IoT Smart Home Devices Security Assessment

Client Overview

A smart home device vendor needed a security assessment of their connected devices: firmware, cloud API, and OTA update mechanism. They wanted to identify vulnerabilities before a major product launch and ensure they could respond to security questionnaires from retailers and partners.

Industry: IoT / Consumer
Challenge: Firmware, API, and OTA security; no prior dedicated IoT security testing
Engagement: 4 weeks (scoping, firmware analysis, API testing, OTA review, report, remediation support)

Scoping & Requirements

Scope: Device firmware (extracted with client approval); device-cloud API; OTA update flow; mobile app API used by devices. Out of scope: physical device destruction. Success criteria: Critical/high in firmware and API remediated; OTA integrity and authentication validated. Rules of engagement: testing on lab devices; no testing on customer devices.

Methodology & Test Cases

Firmware analysis (extraction, file system, credentials, debug interfaces), API testing (auth, authorization, injection, rate limiting), and OTA testing (signature verification, downgrade, replay). Test cases included:

Area	Test Cases Performed
Firmware	Extraction and analysis; hardcoded secrets; debug ports; insecure services
API	Device auth and provisioning; IDOR; command injection; replay attacks
OTA	Unsigned or weakly signed updates; downgrade; MITM; availability

Tools: Binwalk, firmware mod kit, Burp, custom scripts. Standards: OWASP IoT Top 10, NIST.

Findings & Vulnerabilities

18 findings (4 critical, 6 high, 5 medium, 3 low). Critical included:

Critical: OTA updates were not cryptographically verified; attacker could push malicious firmware if they could MITM device traffic.

High: Device API allowed one device to receive another device's commands due to IDOR on device ID. Affected: command API.

Remediation support included OTA signing design, API authorization fixes, and secure provisioning guidance. Client implemented fixes over 4 weeks; we retested and confirmed critical/high closure.

Results & Impact

            90% risk reduction; critical and high reduced to zero after remediation.
OTA now uses signed updates; API enforces device ownership checks.
Client able to answer partner security questionnaires with confidence.

        

"Specialist IoT testing we could not find elsewhere. Worth every penny."

— Product Security Manager, Smart Home Vendor

Key Takeaways

Firmware and OTA security are often the highest risk in IoT. For similar organizations: scope OTA and device-cloud API from the start; plan for firmware signing and secure boot; consider recurring assessments as products evolve.