CVE-2021-0969 in Android
Summary
by MITRE • 12/15/2021
In getTitle of AccessPoint.java, there is a possible unhandled exception due to a missing null check. This could lead to remote denial of service if a proximal Wi-Fi AP provides invalid information with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-10 Android-11Android ID: A-199922685
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Analysis
by VulDB Data Team • 12/18/2021
The vulnerability identified as CVE-2021-0969 resides within the Android operating system's Wi-Fi connectivity handling mechanism, specifically in the AccessPoint.java component that manages wireless access point information. This flaw represents a classic null pointer exception scenario that can be exploited to cause system instability. The vulnerability manifests when the getTitle method fails to properly validate input data from wireless access points, creating a potential pathway for denial of service attacks. The issue is particularly concerning because it operates at the system level where Wi-Fi connectivity management occurs, making it accessible to nearby wireless devices without requiring any special privileges or user interaction beyond the initial connection attempt.
The technical implementation flaw stems from inadequate input validation within the wireless access point information parsing logic. When a proximal Wi-Fi access point provides malformed or incomplete data structures, the getTitle method does not perform proper null checks before attempting to process the information. This missing validation creates a condition where the application attempts to access a null reference, resulting in an unhandled exception that can crash the Wi-Fi management service. The vulnerability aligns with CWE-476 which specifically addresses null pointer dereference conditions, and represents a direct violation of proper defensive programming practices. The lack of input sanitization and validation mechanisms means that any malicious or malformed Wi-Fi beacon information can trigger this exception chain.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively render Wi-Fi connectivity management unusable for affected devices. An attacker positioned within proximity to a target device can exploit this weakness by broadcasting specially crafted Wi-Fi beacon frames that contain invalid or missing title information. This attack vector requires no additional privileges and can be executed from a distance, making it particularly dangerous in public environments or areas with high Wi-Fi density. The remote denial of service condition affects the core Wi-Fi functionality, potentially preventing users from connecting to networks or maintaining existing connections, which can severely impact device usability and productivity. According to ATT&CK framework, this vulnerability maps to T1499.004 which covers network denial of service attacks, and T1059.007 for command and control through network protocols.
Mitigation strategies for CVE-2021-0969 should focus on implementing robust input validation and exception handling within the wireless access point processing code. The primary fix involves adding comprehensive null checks before any data access operations in the getTitle method, ensuring that all input parameters are properly validated before processing. Android security patches addressing this vulnerability typically include enhanced error handling routines that gracefully manage malformed Wi-Fi information without crashing the system. Device manufacturers should implement additional network monitoring capabilities to detect and isolate malicious Wi-Fi beacon activity, while also ensuring that the system can recover automatically from such exceptions without requiring user intervention. Regular security updates and firmware patches remain crucial for maintaining system integrity, as this vulnerability represents a fundamental flaw in the wireless connectivity stack that could potentially be exploited in more sophisticated attacks if left unaddressed.