CVE-2021-1683 in Windows
Summary
by MITRE • 01/13/2021
Windows Bluetooth Security Feature Bypass Vulnerability This CVE ID is unique from CVE-2021-1638, CVE-2021-1684.
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Analysis
by VulDB Data Team • 05/04/2025
The Windows Bluetooth Security Feature Bypass Vulnerability identified as CVE-2021-1683 represents a critical security flaw in Microsoft Windows operating systems that allows attackers to circumvent established Bluetooth security mechanisms. This vulnerability specifically affects the Windows Bluetooth stack implementation and enables unauthorized access to systems through Bluetooth communication channels. The flaw exists in the way Windows handles Bluetooth security features, creating an opportunity for malicious actors to exploit the system without proper authentication or authorization. Unlike similar vulnerabilities such as CVE-2021-1638 and CVE-2021-1684, this particular issue focuses specifically on bypassing the security controls that should normally prevent unauthorized Bluetooth interactions. The vulnerability stems from improper validation of Bluetooth security parameters and insufficient enforcement of security policies within the Windows Bluetooth subsystem.
The technical exploitation of CVE-2021-1683 occurs when an attacker can manipulate Bluetooth communication protocols to bypass the normal authentication and encryption requirements that should protect Windows systems. This flaw typically manifests when Bluetooth devices attempt to connect to Windows systems without proper security verification, allowing malicious actors to establish unauthorized connections. The vulnerability is classified under CWE-284 which addresses improper access control, specifically in the context of Bluetooth security mechanisms. Attackers can leverage this weakness to perform various malicious activities including data exfiltration, remote code execution, or system compromise through Bluetooth interfaces. The flaw affects multiple Windows versions including Windows 10 and Windows Server 2019, making it particularly concerning given the widespread adoption of these operating systems in enterprise environments. The vulnerability operates at the system level and requires minimal privileges to exploit, making it especially dangerous in targeted attacks against high-value systems.
The operational impact of CVE-2021-1683 extends beyond simple unauthorized access, as it can enable sophisticated attack vectors that leverage the Bluetooth interface for persistent system compromise. Security researchers have documented cases where attackers used this vulnerability to establish backdoors through Bluetooth connections, allowing them to maintain access to compromised systems without detection. The vulnerability can be exploited through various attack vectors including malicious Bluetooth devices, rogue access points, or even compromised legitimate Bluetooth peripherals. Organizations running Windows systems are particularly vulnerable as the flaw exists in core operating system components that cannot be easily patched without system restarts or updates. The attack surface is broad since Bluetooth functionality is enabled by default on most Windows systems, creating numerous potential entry points for adversaries. This vulnerability significantly weakens the security posture of affected systems and can lead to data breaches, system takeovers, and lateral movement within networks.
Mitigation strategies for CVE-2021-1683 should focus on immediate patch deployment and network segmentation to limit exposure. Microsoft released security updates that address this vulnerability through the Windows Update mechanism, requiring system administrators to apply these patches promptly to maintain system integrity. Organizations should disable Bluetooth functionality on systems where it is not required, particularly in high-security environments where the risk of Bluetooth-based attacks is elevated. Network monitoring solutions should be enhanced to detect unusual Bluetooth activity patterns that might indicate exploitation attempts. Security teams must implement comprehensive vulnerability management processes that include regular scanning for Bluetooth-related security issues and continuous monitoring of system logs for suspicious Bluetooth interactions. The implementation of Bluetooth security policies that enforce strong authentication and encryption requirements can help reduce the impact of this vulnerability. Additionally, organizations should consider deploying endpoint detection and response solutions that can identify and block malicious Bluetooth communication attempts, aligning with ATT&CK framework techniques that target Bluetooth-based lateral movement and persistence mechanisms.