CVE-2021-0889 in Android
Summary
by MITRE • 12/15/2021
In Android TV , there is a possible silent pairing due to lack of rate limiting in the pairing flow. This could lead to remote code execution with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-8.1 Android-9Android ID: A-180745296
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Analysis
by VulDB Data Team • 12/15/2021
This vulnerability exists within the Android TV pairing mechanism where insufficient rate limiting allows for rapid, automated pairing attempts that can bypass normal security controls. The flaw manifests in the Bluetooth or wireless pairing protocols used by Android TV devices, where the system fails to implement adequate throttling measures to prevent excessive connection requests. This weakness creates a pathway for attackers to perform silent pairing operations without requiring user intervention or explicit interaction, effectively circumventing the normal authentication and authorization processes that should safeguard device access. The vulnerability affects multiple Android versions including Android 8.1, 9, 10, 11, and 12, indicating it represents a persistent flaw in the platform's wireless pairing architecture. From a cybersecurity perspective, this issue aligns with CWE-307 which addresses improper restriction of consecutive authentications, and falls under ATT&CK technique T1566 for initial access through spearphishing attachments or links.
The technical implementation of this vulnerability allows for rapid successive pairing attempts that can overwhelm the device's authentication mechanisms. Attackers can exploit this by rapidly cycling through pairing sequences without triggering the normal rate limiting controls that would typically prevent brute force attacks on the pairing process. This creates a scenario where an attacker can programmatically establish a trusted pairing relationship with the Android TV device, gaining access to all functions and services available to paired devices. The lack of user interaction requirement makes this particularly dangerous as it enables fully automated attacks that can be deployed without any human involvement or awareness from the device owner.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential remote code execution capabilities. Once an attacker successfully establishes a silent pairing relationship, they can leverage this trusted connection to execute arbitrary code on the Android TV platform without requiring additional privileges or escalation techniques. This represents a severe compromise of device security since the pairing process is designed to establish trust boundaries, and the vulnerability allows bypassing these fundamental security controls. The implications include full access to media content, system configuration changes, potential network reconnaissance, and the ability to use the compromised device as a pivot point for attacks on other networked devices.
Mitigation strategies should focus on implementing robust rate limiting controls within the pairing protocols to prevent excessive connection attempts. System administrators and device manufacturers should ensure that pairing mechanisms enforce appropriate time delays between consecutive pairing requests and implement connection attempt counters to detect and block automated attack patterns. Additionally, enhancing the authentication requirements for pairing operations, such as requiring explicit user confirmation even for trusted devices, would help prevent unauthorized silent pairings. The fix should address the root cause by implementing proper flow control mechanisms that align with security best practices for wireless device pairing protocols. Organizations should also consider network-level monitoring to detect unusual pairing activity patterns and implement device-specific security policies that restrict pairing capabilities based on device location and user context.