CVE-2020-10135 in Bluetooth BR EDR Core
Summary
by MITRE
Legacy pairing and secure-connections pairing authentication in Bluetooth® BR/EDR Core Specification v5.2 and earlier may allow an unauthenticated user to complete authentication without pairing credentials via adjacent access. An unauthenticated, adjacent attacker could impersonate a Bluetooth BR/EDR master or slave to pair with a previously paired remote device to successfully complete the authentication procedure without knowing the link key.
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Analysis
by VulDB Data Team • 11/13/2024
This vulnerability exists within the Bluetooth BR/EDR (Baseband/Enhanced Data Rate) pairing mechanisms defined in the Bluetooth Core Specification versions 5.2 and earlier. The flaw specifically affects both legacy pairing and secure connections pairing procedures, creating a critical security gap that allows unauthorized access to Bluetooth devices. The vulnerability stems from insufficient authentication checks during the pairing process, enabling an attacker to complete authentication without possessing valid pairing credentials.
The technical implementation of this vulnerability exploits the pairing protocols' trust model where devices accept pairing requests from adjacent attackers without proper verification of the attacker's credentials. In legacy pairing scenarios, the system relies on the link key for authentication, but the vulnerability allows an unauthenticated attacker to bypass this requirement entirely. The secure connections pairing, while designed to be more robust, still contains implementation flaws that permit similar unauthorized access. This occurs because the authentication flow does not adequately validate that the pairing request originates from a legitimate device that possesses the required link key or cryptographic credentials.
The operational impact of this vulnerability is significant for any device running Bluetooth BR/EDR protocols in versions 5.2 or earlier. Adjacent attackers can exploit this weakness to impersonate legitimate Bluetooth devices and establish unauthorized connections with previously paired devices. This creates a persistent security risk where attackers can access devices that were previously considered secure, potentially gaining access to sensitive data, control over device functions, or enabling further attacks through the compromised device. The vulnerability is particularly dangerous because it operates without requiring proximity to the device or knowledge of existing pairing credentials, making it difficult to detect and prevent.
Mitigation strategies for this vulnerability include upgrading to Bluetooth Core Specification version 5.3 or later, which addresses these pairing authentication flaws through enhanced cryptographic protocols and improved authentication mechanisms. Organizations should also implement additional security controls such as disabling legacy pairing modes when secure connections are available, regularly reviewing and updating pairing credentials, and employing network segmentation to limit the impact of potential breaches. The vulnerability aligns with CWE-287 (Improper Authentication) and can be categorized under ATT&CK technique T1046 (Network Service Scanning) and T1072 (Software Deployment Tools) when attackers leverage this weakness to establish persistent access. Device manufacturers should also consider implementing automatic pairing credential rotation and enhanced logging mechanisms to detect unauthorized pairing attempts.