CVE-2022-20336 in Android
Summary
by MITRE • 08/12/2022
In Settings, there is a possible installed application disclosure due to a missing permission check. This could lead to local information disclosure of applications allow-listed to use the network during VPN lockdown mode with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-13Android ID: A-177239688
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Analysis
by VulDB Data Team • 09/10/2022
This vulnerability resides within the Android Settings application and represents a critical permission oversight that could enable unauthorized access to installed application information. The flaw exists in the VPN lockdown mode functionality where the system fails to properly validate permissions before disclosing network-allowlisted applications. This represents a violation of the principle of least privilege and demonstrates a failure in access control mechanisms that should prevent unauthorized enumeration of application data. The vulnerability specifically affects Android 13 systems and is identified by the Android ID A-177239688, highlighting the importance of proper permission validation in system-level components.
The technical implementation flaw stems from the missing permission check within the Settings component that manages VPN lockdown mode configurations. When applications are allow-listed to use the network during VPN lockdown, the system should enforce proper authorization boundaries to prevent unauthorized disclosure of this information. The vulnerability allows any local process to enumerate applications that have been granted network access during VPN lockdown, bypassing the expected security controls. This type of information disclosure vulnerability aligns with CWE-200, which addresses "Information Exposure" and represents a failure to properly enforce access controls. The flaw essentially creates an information leak channel that could reveal sensitive application configuration data to unauthorized parties.
The operational impact of this vulnerability extends beyond simple information disclosure as it could enable attackers to map the network permissions of installed applications, potentially aiding in further exploitation attempts. An attacker with local access could leverage this vulnerability to discover which applications are permitted to bypass VPN restrictions, providing insights into the security posture of the device. This information could be used to craft targeted attacks against applications that have elevated network privileges during VPN lockdown mode. The vulnerability's exploitation requires no additional execution privileges and does not necessitate user interaction, making it particularly concerning as it can be exploited automatically by any local process. This characteristic places the vulnerability in the ATT&CK matrix under T1083 (File and Directory Discovery) and T1566 (Phishing for Information) as it enables unauthorized discovery of system information.
Mitigation strategies should focus on implementing proper permission validation within the Settings component and ensuring that network-allowlisted application information is only accessible to authorized processes. Android security updates should enforce strict access controls for VPN lockdown mode configurations and implement proper authorization checks before disclosing application network permissions. System administrators should monitor for unauthorized access to network configuration data and ensure that all applications with elevated privileges during VPN lockdown are properly audited. The fix should involve adding mandatory permission checks that validate whether the requesting process has appropriate authorization to access the network allow-list information, thereby preventing unauthorized disclosure while maintaining legitimate functionality for authorized users.