CVE-2023-21317 in Android
Summary
by MITRE • 10/30/2023
In ContentService, 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 with no additional execution privileges needed. User interaction is not needed for exploitation.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/22/2023
The vulnerability identified as CVE-2023-21317 resides within the ContentService component of a mobile operating system platform where an information disclosure flaw exists that allows unauthorized determination of application installation status. This weakness stems from insufficient access controls and improper validation of requests that should otherwise require explicit query permissions to ascertain whether specific applications are present on the device. The vulnerability manifests through side channel attacks where an attacker can infer the existence of applications by observing system behavior patterns or response timing differences that reveal whether a particular application is installed. This represents a significant privacy and security concern as it provides adversaries with unauthorized reconnaissance capabilities that could be leveraged to build comprehensive profiles of device contents and user behavior patterns without requiring any elevated privileges or user interaction. The flaw operates at the system level within the ContentService framework which is responsible for managing content access and application metadata, making it a critical component in the overall security architecture.
The technical implementation of this vulnerability exploits timing variations or response characteristics that differ based on whether an application is installed or not. When a request is made to query application information, the system's response behavior changes depending on the application's presence, creating a side channel that can be monitored and analyzed. This type of information disclosure vulnerability falls under the category of timing attacks and information leakage through system response patterns. The flaw essentially allows an attacker to perform application enumeration without proper authorization, as the system provides indirect information about installed applications through its response behavior rather than through direct query results. This creates a covert channel through which sensitive information about device configuration and installed applications can be extracted, representing a clear violation of access control principles and confidentiality requirements. The vulnerability is particularly concerning because it operates without requiring any additional execution privileges beyond basic system access, making it accessible to attackers with minimal privileges.
The operational impact of CVE-2023-21317 extends beyond simple information disclosure to create potential pathways for more sophisticated attacks and privacy violations. An attacker can use this vulnerability to build detailed inventories of installed applications, which may include sensitive applications such as banking, messaging, or productivity tools that could be targeted for further exploitation. The lack of user interaction requirement makes this vulnerability particularly dangerous as it can be exploited passively during normal system operation without alerting users to the reconnaissance activity. This type of vulnerability aligns with attack patterns described in the attack tree methodology where information disclosure serves as a foundational step for more complex attack vectors. The vulnerability creates a persistent threat surface that can be exploited repeatedly without detection, potentially enabling adversaries to establish long-term reconnaissance capabilities against targeted devices. From a compliance standpoint, this vulnerability could violate privacy regulations and security standards such as those outlined in iso/iec 27001 and nist cybersecurity framework.
Mitigation strategies for CVE-2023-21317 should focus on implementing proper access controls and eliminating side channel information leakage mechanisms within the ContentService component. System designers must ensure that all application query operations return consistent responses regardless of whether the target application exists, eliminating timing variations that could be exploited. This requires implementing constant-time response mechanisms and removing information that could be inferred from system behavior patterns. The fix should involve modifying the ContentService to normalize response behavior for all application queries, ensuring that the system does not provide indirect information about application installation status through response characteristics. Additionally, implementing proper input validation and access control checks at the ContentService level will prevent unauthorized queries from being processed in a way that reveals application information. Security patches should address the root cause by ensuring that all queries return consistent results and that the system does not differentiate its response behavior based on application existence. This vulnerability demonstrates the importance of considering side channel attacks during security design phases and highlights the need for comprehensive threat modeling that accounts for information leakage through system behavior rather than just direct data access vulnerabilities. The remediation approach should align with defense-in-depth principles and include proper auditing of system responses to prevent similar information disclosure issues from emerging in other components of the platform.