CVE-2021-0144 in BSSA
Summary
by MITRE • 07/15/2021
Insecure default variable initialization for the Intel BSSA DFT feature may allow a privileged user to potentially enable an escalation of privilege via local access.
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Analysis
by VulDB Data Team • 07/18/2021
The vulnerability identified as CVE-2021-0144 resides within the Intel BSSA DFT (Built-in Self-Test Digital Fault Testing) feature implementation, representing a critical security weakness that exploits insecure default variable initialization practices. This flaw specifically affects systems utilizing Intel's hardware-based security mechanisms and manifests when the BSSA DFT component initializes variables with predictable or insecure default values during system boot or operational cycles. The vulnerability operates at the hardware level, leveraging the inherent trust placed in Intel's security subsystems to create a potential pathway for privilege escalation.
The technical flaw stems from the improper initialization of critical variables within the BSSA DFT module, which typically handles hardware self-testing and fault detection functions. When these variables are not properly secured or randomized during initialization, they may retain predictable values or remain in vulnerable states that can be manipulated by a privileged local user. This insecure initialization process creates a condition where an attacker with local access and elevated privileges can exploit the predictable variable states to gain unauthorized access to higher-privilege execution contexts. The vulnerability does not require network access or external exploitation vectors, making it particularly concerning as it only requires local system access to potentially compromise the entire security posture.
The operational impact of CVE-2021-0144 extends beyond simple privilege escalation, as it fundamentally undermines the integrity of Intel's hardware security mechanisms. A successful exploitation could allow an attacker to bypass hardware-level security controls, potentially enabling further attacks including but not limited to system compromise, data exfiltration, or persistent backdoor establishment. The vulnerability affects systems where the BSSA DFT feature is actively utilized for hardware testing and validation, which includes enterprise servers, data center infrastructure, and embedded systems that rely on Intel's hardware security features. The attack surface is particularly concerning in environments where privileged accounts are common or where local access is not strictly controlled.
Mitigation strategies for this vulnerability require both firmware-level updates from Intel and careful system administration practices. System administrators should immediately apply the latest Intel firmware updates that address the insecure variable initialization issue within the BSSA DFT implementation. Additionally, implementing strict access controls and monitoring for unusual system behavior can help detect potential exploitation attempts. The vulnerability aligns with CWE-665 and CWE-254 categories related to insecure initialization of variables and improper privilege management. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques and can be leveraged in combination with other local exploits to establish persistent access. Organizations should also consider implementing hardware security modules and additional monitoring of system boot processes to detect anomalous behavior that might indicate exploitation attempts.