CVE-2023-21296 in Android
Summary
by MITRE • 10/30/2023
In Permission, 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 escalation of privilege with no additional execution privileges needed. User interaction is needed for exploitation.
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Analysis
by VulDB Data Team • 11/22/2023
The vulnerability identified as CVE-2023-21296 represents a significant security flaw within the Android permission system that enables unauthorized determination of application installation status through side channel information disclosure. This issue resides in the core permission framework that governs how applications interact with system resources and other applications on Android devices. The vulnerability exploits a fundamental weakness in how the system handles permission queries and application state information, creating an unintended information leakage channel that bypasses normal security boundaries. Attackers can leverage this flaw to gain insights into the presence of specific applications on a device without requiring explicit permission queries or elevated privileges, fundamentally undermining the privacy and security assumptions that govern application sandboxing.
The technical implementation of this vulnerability stems from how the Android system processes permission checks and communicates application state information. When applications attempt to perform permission operations, the system's response timing, memory access patterns, or other observable behaviors can inadvertently reveal whether a target application is installed on the device. This side channel leakage occurs because the permission system does not properly mask the differences in response behavior between scenarios where an application exists versus where it does not exist. The vulnerability specifically affects how the system handles permission checking operations and exposes information through timing variations or memory access patterns that can be measured and analyzed by malicious actors. This type of information disclosure aligns with CWE-203, which describes "Observable Behavioral Vulnerability" where system behavior reveals sensitive information about internal state or configuration.
The operational impact of this vulnerability extends beyond simple information disclosure, creating potential pathways for local privilege escalation attacks. Attackers who can successfully exploit this vulnerability gain the ability to determine application installation status without requiring additional permissions or execution privileges, which can serve as a foundation for more sophisticated attacks. The requirement for user interaction indicates that exploitation typically occurs through social engineering or targeted phishing campaigns where users might be诱导 to perform specific actions that trigger the vulnerable code path. This user interaction requirement makes the attack more plausible in real-world scenarios but does not eliminate the underlying security risk. The vulnerability essentially allows attackers to map the application landscape of a device without triggering traditional permission monitoring systems, potentially enabling targeted attacks against specific applications or user profiles. The privilege escalation aspect arises because knowing which applications are installed can provide attackers with valuable intelligence for crafting more effective attacks against those applications or their associated data.
Mitigation strategies for CVE-2023-21296 must address the fundamental information leakage in the permission system while maintaining system functionality and user experience. The most effective approach involves implementing proper input sanitization and response uniformity in permission checking operations, ensuring that all permission queries return consistent timing and behavior regardless of whether the target application exists. System-level patches should focus on eliminating side channel information leakage by normalizing the response behavior of permission checks and preventing timing variations that could reveal application installation status. Additionally, developers should implement proper access controls and validate all permission-related operations to prevent unauthorized information disclosure. The remediation process should include comprehensive testing to ensure that permission checking operations no longer exhibit observable differences based on application installation status. Security teams should also implement monitoring for unusual permission query patterns that might indicate exploitation attempts, and consider implementing application sandboxing measures that further isolate permission checking operations to prevent information leakage. This vulnerability demonstrates the importance of considering side channel attacks in security design and aligns with ATT&CK technique T1068, which covers "Local Privilege Escalation" through the exploitation of system vulnerabilities.