CVE-2022-32503 in Nuki
Summary
by MITRE • 05/14/2024
An issue was discovered on certain Nuki Home Solutions devices. An attacker with physical access to this JTAG port may be able to connect to the device and bypass both hardware and software security protections. This affects Nuki Keypad before 1.9.2 and Nuki Fob before 1.8.1.
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Analysis
by VulDB Data Team • 10/30/2024
The vulnerability identified as CVE-2022-32503 represents a critical security flaw in Nuki Home Solutions devices that exposes a fundamental weakness in their physical security architecture. This vulnerability specifically targets the JTAG (Joint Test Action Group) port, which serves as a standard interface for testing and debugging embedded systems during development and manufacturing processes. The flaw allows an attacker with physical access to the device to establish a connection through this port and subsequently bypass all hardware and software security protections that are normally in place to safeguard the device. This represents a severe escalation from typical software-based vulnerabilities, as it operates at the hardware level and fundamentally undermines the device's security posture.
The technical implementation of this vulnerability stems from the improper protection or exposure of the JTAG interface on Nuki devices, particularly affecting the Nuki Keypad models prior to version 1.9.2 and Nuki Fob models prior to version 1.8.1. The JTAG port, when left accessible without proper physical security measures, provides a direct pathway to the device's memory and processing units, enabling attackers to execute arbitrary code, modify firmware, and potentially extract sensitive cryptographic keys or authentication credentials. This flaw aligns with CWE-254, which addresses "Security Features" and specifically highlights weaknesses in physical security controls that allow unauthorized access to critical system components. The vulnerability demonstrates a failure in the principle of least privilege at the hardware level, where a debug interface intended for legitimate development purposes remains accessible in production environments without adequate physical safeguards.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it fundamentally compromises the security model of the entire Nuki ecosystem. An attacker who gains physical access to a device through the JTAG port can effectively neutralize all security measures that would normally protect against remote attacks or unauthorized physical access. This includes bypassing authentication mechanisms, disabling security features, and potentially installing malicious firmware that could persist even after device reboots or power cycles. The vulnerability creates a backdoor that allows attackers to compromise the device's cryptographic integrity, potentially enabling them to gain access to all connected smart home systems or networks that rely on these security devices for authentication and access control. This aligns with ATT&CK technique T1014, which covers "Rootkit" and "System Firmware" compromises, as the vulnerability allows for low-level system manipulation that can persist across traditional security boundaries.
Mitigation strategies for this vulnerability must address both the immediate physical exposure and the broader security architecture implications. The primary remediation involves updating affected devices to the patched versions mentioned in the vulnerability description, specifically Nuki Keypad version 1.9.2 and Nuki Fob version 1.8.1, which should include proper physical protection measures for the JTAG interface. Organizations should implement strict physical security controls to prevent unauthorized access to devices, including securing device locations, implementing tamper-evident seals, and establishing procedures for device inspection and maintenance. The vulnerability also underscores the importance of following security best practices in embedded system design, including proper configuration of debug interfaces during production, implementing secure boot mechanisms, and ensuring that physical security controls are integrated into the overall security architecture. Network segmentation and monitoring should be enhanced to detect potential compromise indicators, and regular security assessments should be conducted to identify similar vulnerabilities in other embedded systems within the organization's infrastructure.