CVE-2019-5679 in Shield TV Experience
Summary
by MITRE
NVIDIA Shield TV Experience prior to v8.0, NVIDIA Tegra bootloader contains a vulnerability in nvtboot where the Trusted OS image is improperly authenticated, which may lead to code execution, denial of service, escalation of privileges, and information disclosure, code execution, denial of service, or escalation of privileges
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/22/2020
The vulnerability identified as CVE-2019-5679 affects the NVIDIA Shield TV Experience software ecosystem prior to version 8.0 and specifically targets the Tegra bootloader implementation. This issue resides within the nvtboot component which serves as a critical boot stage responsible for authenticating the Trusted OS image. The flaw represents a significant security weakness in the hardware security architecture of NVIDIA's embedded systems, particularly impacting devices that utilize Tegra processors. The vulnerability stems from inadequate cryptographic verification mechanisms during the boot process, creating opportunities for malicious actors to exploit the system's trust model. This weakness directly impacts the integrity verification of the operating system components that are critical for maintaining system security and stability.
The technical implementation of this vulnerability occurs at the bootloader level where the nvtboot module fails to properly validate the digital signatures or cryptographic hashes of the Trusted OS image before loading it into memory. This authentication failure creates a window of opportunity for attackers to substitute or modify the legitimate Trusted OS components with malicious code. The flaw operates at a fundamental level of the system's security architecture, bypassing traditional software-based protections that rely on the assumption that the bootloader components remain untampered. This represents a classic case of insufficient input validation and authentication checks, which aligns with CWE-284 access control vulnerabilities and CWE-327 weak cryptographic algorithms. The vulnerability is particularly concerning because it affects the very foundation upon which all subsequent security measures depend, essentially undermining the entire security framework of the device.
The operational impact of this vulnerability extends across multiple security domains including code execution, denial of service, privilege escalation, and information disclosure. An attacker who successfully exploits this vulnerability could potentially gain unauthorized access to execute arbitrary code within the Trusted Execution Environment, effectively bypassing hardware-level security controls. The ability to perform privilege escalation means that malicious code could gain elevated system privileges, potentially allowing full control over the device. Additionally, the vulnerability could enable information disclosure attacks where sensitive data stored within the Trusted OS environment becomes accessible to unauthorized parties. This type of vulnerability would be particularly attractive to threat actors targeting embedded devices for reconnaissance, lateral movement, or establishing persistent access points within network environments. The impact aligns with ATT&CK techniques related to privilege escalation and initial access through bootkits and firmware attacks.
Mitigation strategies for this vulnerability require immediate firmware updates to version 8.0 or later where NVIDIA has implemented proper cryptographic authentication mechanisms for the Trusted OS image. System administrators and device manufacturers should prioritize deployment of these security patches across all affected NVIDIA Shield TV devices and Tegra-based platforms. The remediation process should include thorough verification of the update process to ensure that the new authentication mechanisms are properly implemented and functioning. Organizations should also consider implementing additional monitoring and detection measures to identify potential exploitation attempts, particularly focusing on unusual boot patterns or unauthorized modifications to system components. Given the nature of the vulnerability, it is essential to maintain proper security hygiene including regular firmware updates, secure boot configurations, and implementation of network segmentation to limit the potential impact of successful exploitation attempts. The vulnerability highlights the critical importance of secure boot processes and proper cryptographic implementation in embedded systems, emphasizing that hardware-level security mechanisms must be robustly implemented to prevent such fundamental trust model violations.