CVE-2016-2497 in Android
Summary
by MITRE
services/core/java/com/android/server/pm/PackageManagerService.java in the framework APIs in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-08-01 allows attackers to increase intent-filter priority via a crafted application, aka internal bug 27450489.
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Analysis
by VulDB Data Team • 09/12/2022
The vulnerability described in CVE-2016-2497 represents a critical flaw in Android's package management system that allows malicious applications to manipulate intent-filter priority rankings. This issue exists within the PackageManagerService.java file in the Android framework APIs, specifically affecting versions prior to the mentioned security patches. The vulnerability enables attackers to craft applications that can elevate their own intent-filter priorities above legitimate system applications, potentially leading to malicious intent interception and unauthorized application behavior. The flaw operates at the core level of Android's application framework, making it particularly dangerous as it can affect the fundamental application routing mechanisms that govern how intents are delivered between applications.
The technical implementation of this vulnerability stems from insufficient validation of intent-filter priority values during package installation and update processes. When an application is installed or updated, the PackageManagerService processes intent filters to determine how intents should be routed to different applications. The vulnerability allows attackers to specify artificially high priority values in their intent filters, which the system accepts without proper verification. This can result in the malicious application receiving intents that should normally be delivered to legitimate applications. The issue is particularly concerning because intent filters are fundamental to Android's inter-application communication model, and manipulating their priority can lead to various attack vectors including intent interception, application hijacking, and potentially privilege escalation within the application ecosystem.
The operational impact of this vulnerability extends beyond simple application behavior manipulation to potentially compromise the entire Android application sandbox model. Attackers can exploit this weakness to create malicious applications that masquerade as legitimate system services or user applications, intercepting sensitive communications and data flows. This vulnerability can be particularly dangerous in environments where Android devices handle sensitive information, as it allows attackers to position themselves in the middle of legitimate application communication channels. The attack surface is broad since any application that relies on intent-based communication can be affected, including system applications, third-party applications, and even core Android services that depend on proper intent routing for their operation. This weakness undermines the fundamental trust model of Android's application ecosystem where applications should be properly sandboxed and intent routing should be deterministic and secure.
Mitigation strategies for CVE-2016-2497 require immediate patching of affected Android versions to the latest security updates provided by Google. Organizations should implement comprehensive application vetting processes that include checking for potentially malicious intent-filter configurations in third-party applications. The vulnerability aligns with CWE-264, which addresses permissions, privileges, and access controls, and can be mapped to ATT&CK technique T1059, specifically focusing on the use of system services for privilege escalation. Network administrators should consider implementing mobile device management solutions that can detect and prevent installation of applications with suspicious intent-filter configurations. Additionally, developers should be educated about proper intent-filter implementation practices and the importance of validating priority values in their applications. Regular security audits of installed applications should be conducted to identify any applications that may be exploiting this vulnerability, and system monitoring should be implemented to detect unusual intent-filter behavior patterns that could indicate exploitation attempts.