CVE-2021-1638 in Windows
Summary
by MITRE • 01/13/2021
Windows Bluetooth Security Feature Bypass Vulnerability This CVE ID is unique from CVE-2021-1683, CVE-2021-1684.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/09/2024
The Windows Bluetooth Security Feature Bypass Vulnerability identified as CVE-2021-1638 represents a critical security flaw in Microsoft Windows operating systems that undermines the fundamental security controls governing Bluetooth communications. This vulnerability specifically targets the security mechanisms implemented within the Windows Bluetooth stack, creating a pathway for unauthorized access and privilege escalation. The flaw affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern across enterprise and consumer environments. The vulnerability stems from improper validation of Bluetooth security features during device pairing and connection processes, allowing malicious actors to bypass established security protocols.
The technical implementation of this vulnerability resides within the Windows Bluetooth subsystem where the security feature bypass occurs during the authentication and authorization phases of Bluetooth device connections. Attackers can exploit this flaw by establishing a malicious Bluetooth connection that circumvents the normal security checks typically enforced by Windows. This allows them to gain unauthorized access to Bluetooth services and potentially execute arbitrary code with elevated privileges. The vulnerability is classified under CWE-284 which specifically addresses improper access control, and aligns with ATT&CK technique T1046 for network service scanning and T1068 for exploit for privilege escalation. The flaw manifests when Windows fails to properly validate the security context of Bluetooth connections, particularly during the pairing process where security credentials should be rigorously verified.
The operational impact of CVE-2021-1638 extends beyond simple unauthorized access, as it enables sophisticated attack vectors that can lead to complete system compromise. An attacker exploiting this vulnerability can potentially establish persistent Bluetooth connections that maintain access even after initial compromise, creating a foothold for further lateral movement within networks. The vulnerability's implications are particularly concerning in enterprise environments where Bluetooth devices are commonly used for authentication tokens, access control systems, and IoT device management. Organizations with Windows systems running in close proximity to Bluetooth-enabled devices face significant risk of unauthorized physical access or data exfiltration. The security bypass allows attackers to perform actions that would normally require administrator privileges, including installing malicious software, modifying system configurations, and accessing sensitive data repositories.
Mitigation strategies for CVE-2021-1638 should focus on immediate patch deployment through Microsoft's regular security updates, which address the core validation issues within the Bluetooth subsystem. Organizations must implement network segmentation to isolate Bluetooth-enabled systems from critical infrastructure and establish strict Bluetooth device management policies. Disabling Bluetooth functionality when not required provides an additional layer of protection, while monitoring for unusual Bluetooth connection patterns can help detect potential exploitation attempts. Security teams should also consider implementing endpoint detection and response solutions that can identify anomalous Bluetooth behavior and alert on unauthorized pairing attempts. The vulnerability highlights the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that protect against multiple attack vectors. Organizations should conduct vulnerability assessments to identify systems running affected Windows versions and prioritize remediation efforts based on risk exposure. Regular security awareness training for personnel regarding Bluetooth security risks and proper device management practices further strengthens the overall security posture against this and similar vulnerabilities.