CVE-2021-0734 in Android
Summary
by MITRE • 08/11/2022
In Settings, there is a possible way to determine whether an app is installed without query permissions, due to side channel information disclosure. This could lead to local information disclosure of an installed package, without proper query permissions, with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-13Android ID: A-189122911
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Analysis
by VulDB Data Team • 08/11/2022
This vulnerability exists within the Android Settings application where side channel information disclosure allows unauthorized determination of installed applications without proper query permissions. The flaw resides in how the system exposes package information through indirect means that bypass normal permission controls. Attackers can exploit this weakness to enumerate applications installed on a device by observing subtle behavioral differences or information leakage patterns in the Settings interface. The vulnerability specifically affects Android 13 and represents a significant privacy concern as it enables passive reconnaissance of device contents. This type of information disclosure typically falls under CWE-200, which addresses information exposure through side channels, and aligns with ATT&CK technique T1083 for discovering files and directories. The attack requires no user interaction and does not demand additional execution privileges, making it particularly dangerous as it can be exploited silently in the background. The vulnerability stems from improper access control mechanisms within the Settings application that fail to adequately restrict information flow about installed packages.
The technical implementation of this vulnerability involves the Settings application leaking information about installed applications through observable side channels rather than direct API calls. When users interact with Settings or when the system processes certain operations, it inadvertently reveals package information through timing differences, memory patterns, or other indirect indicators. This information leakage occurs even when the attacker lacks the proper permissions typically required to query installed applications. The flaw demonstrates a breakdown in the Android permission model where the system fails to properly isolate package information from unauthorized access attempts. The vulnerability is particularly concerning because it operates at the system level within Settings, which is a trusted application that users frequently interact with, providing numerous opportunities for exploitation. The lack of additional privileges required for exploitation means that even basic user accounts can potentially leverage this weakness, making it accessible to a broad range of threat actors.
The operational impact of this vulnerability extends beyond simple information disclosure as it enables attackers to build comprehensive profiles of target devices. An attacker can use this information to identify installed applications, potentially including sensitive business or personal software, and then tailor more sophisticated attacks based on the discovered package inventory. This reconnaissance capability can lead to targeted phishing attempts, exploitation of known vulnerabilities in specific applications, or social engineering campaigns that leverage knowledge of installed software. The vulnerability also undermines user privacy expectations regarding application isolation and confidentiality. In enterprise environments, this could expose sensitive applications or proprietary software that organizations rely on for security. The implications are particularly severe for users who store sensitive data or conduct confidential work on their devices, as the vulnerability could reveal the presence of applications handling such information. The low barrier to exploitation makes this vulnerability attractive to both automated scanning tools and sophisticated attackers seeking to establish initial footholds.
Mitigation strategies for this vulnerability should focus on strengthening the access control mechanisms within the Settings application and implementing proper isolation of package information. Android security updates should address the root cause by ensuring that package enumeration cannot occur through side channels, regardless of user interaction or application state. System-level protections should be enhanced to prevent information leakage patterns that could reveal installed applications. Organizations should ensure timely deployment of security patches and consider implementing additional monitoring for unusual Settings application behavior. Network administrators should also be aware of this vulnerability when assessing device security postures and may need to implement additional controls to prevent exploitation. The fix should involve proper input validation and output sanitization within Settings to prevent indirect information disclosure while maintaining legitimate functionality. Security researchers should monitor for similar vulnerabilities in other system applications that might expose similar side channel information leakage patterns. The vulnerability highlights the importance of comprehensive security testing that includes side channel analysis and proper permission boundary enforcement.