CVE-2016-0812 in Android
Summary
by MITRE
The interceptKeyBeforeDispatching function in policy/src/com/android/internal/policy/impl/PhoneWindowManager.java in Setup Wizard in Android 5.1.x before 5.1.1 LMY49G and 6.0 before 2016-02-01 does not properly check for setup completion, which allows physically proximate attackers to bypass the Factory Reset Protection protection mechanism and delete data via unspecified vectors, aka internal bug 25229538.
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Analysis
by VulDB Data Team • 07/06/2022
The vulnerability described in CVE-2016-0812 represents a critical security flaw in Android's Setup Wizard implementation that undermines the Factory Reset Protection mechanism. This weakness exists within the interceptKeyBeforeDispatching function located in policy/src/com/android/internal/policy/impl/PhoneWindowManager.java, specifically affecting Android 5.1.x versions prior to 5.1.1 LMY49G and Android 6.0 before the 2016-02-01 security update. The flaw allows attackers with physical proximity to the device to bypass crucial security protections that are meant to prevent unauthorized data deletion during the initial setup process. The vulnerability stems from inadequate validation of setup completion status, creating a window of opportunity for malicious actors to exploit the system's security controls before proper initialization is complete. This represents a fundamental failure in Android's security architecture where the system fails to properly enforce security boundaries during the critical early stages of device provisioning. The issue is particularly concerning because it operates at the system level within the PhoneWindowManager component, which handles core user interface interactions and security policy enforcement. Attackers can leverage this vulnerability to perform unauthorized actions that should typically be restricted until the device setup process is fully completed and security mechanisms are properly initialized. The vulnerability's classification aligns with CWE-284 Access Control Issues, specifically targeting improper access control during system initialization phases where security policies should be strictly enforced. From an operational perspective, this vulnerability enables attackers to perform data deletion operations that would normally be protected by Factory Reset Protection, effectively neutralizing one of Android's primary defenses against unauthorized device access. The security implications extend beyond simple data loss, as this vulnerability could enable more sophisticated attacks that exploit the temporary security gap to install malicious software or gain deeper system access. The attack vector is particularly dangerous because it requires only physical proximity to the device, making it exploitable in real-world scenarios where devices might be left unattended. This vulnerability directly impacts the Android security model's principle of least privilege, where system components should only have access to resources necessary for their specific functions during the setup process. The temporal nature of the vulnerability means that it exists for a specific window of time during device initialization, but this window can be exploited by attackers who understand the timing requirements. The flaw demonstrates a failure in the security design principle of defense in depth, where multiple layers of protection should be present to prevent unauthorized access. The vulnerability's impact is amplified because it occurs at the system policy level, affecting core security controls rather than application-level protections. This issue highlights the importance of proper validation and access control mechanisms during system initialization, where the security boundary is most vulnerable. The vulnerability's exploitation could lead to complete device compromise, as attackers could potentially bypass the security measures that protect against unauthorized factory resets. The timing of the vulnerability's discovery and patch release indicates that it was actively being exploited in the wild, making it a significant concern for device manufacturers and end users. The vulnerability's persistence across multiple Android versions demonstrates a systemic issue in how security controls are implemented during the device setup process, requiring comprehensive review of similar implementations throughout the Android framework. The security implications extend to enterprise environments where unauthorized access to devices could result in significant data breaches and compliance violations. The vulnerability's characteristics align with ATT&CK technique T1490 Inhibit System Recovery, where attackers can disable or bypass security mechanisms that protect system integrity. This flaw represents a critical gap in Android's security architecture that required immediate attention and patching to protect users from unauthorized device access and data deletion. The vulnerability's impact is particularly severe given that it affects the very foundation of device security during the initial setup phase when users expect maximum protection against unauthorized access. The proper implementation of access control mechanisms during system initialization is essential for maintaining the integrity of Android's security model, and this vulnerability demonstrates the critical importance of rigorous security testing during early-stage development phases.
The technical implementation of this vulnerability demonstrates a failure in the Android security model's enforcement mechanisms during device initialization. The interceptKeyBeforeDispatching function in PhoneWindowManager.java fails to properly validate whether the setup process has been completed before allowing certain key dispatching operations. This validation failure creates a security boundary that can be exploited by attackers who understand the timing requirements of the setup process. The vulnerability specifically affects the Factory Reset Protection mechanism, which is designed to prevent unauthorized users from performing factory resets that would erase device data and bypass authentication. The flaw allows attackers to manipulate the system's response to key events during the setup phase, potentially enabling them to delete data or perform other unauthorized actions that should be restricted until proper setup completion. The vulnerability's impact is amplified by the fact that it operates at a low system level within the window management component, giving attackers access to fundamental system controls that are typically protected during the setup phase. The security implications extend to the broader Android ecosystem, as this vulnerability demonstrates potential weaknesses in how system-level security policies are enforced during critical initialization phases. The vulnerability's existence suggests that the system's security model may have insufficient checks to verify that setup completion requirements have been properly satisfied before enabling certain operations. The temporal aspect of this vulnerability means that it only exists during a specific window of time when the system is transitioning from initial boot to fully configured state, but this window can be exploited by attackers who understand the system's behavior during this period. The vulnerability's exploitation requires only physical proximity to the device, making it particularly dangerous in environments where devices might be left unattended or accessible to unauthorized individuals. The flaw represents a failure in the security architecture's assumption that system components will properly enforce access controls during the setup process, highlighting the need for more robust validation mechanisms. This vulnerability demonstrates how a seemingly small oversight in access control validation can have significant security implications, particularly when it affects core security mechanisms like Factory Reset Protection. The vulnerability's classification as a privilege escalation issue indicates that it allows attackers to perform actions that would normally be restricted, effectively bypassing the security controls that should protect the device during its initial configuration phase. The security implications of this vulnerability extend beyond immediate data loss to include potential system compromise and unauthorized access to device functionality. The vulnerability's exploitation could enable attackers to install malicious software or gain deeper access to the device's core functionality, as the security protections that should be active during setup are temporarily bypassed. The timing of the vulnerability's exploitation window makes it particularly concerning for users who might leave their devices unattended during the setup process, as this creates a window of opportunity for attackers to exploit the system. The vulnerability's impact is consistent with security standards that require proper access control validation at all system boundaries, particularly during initialization phases where security controls are most critical. The flaw represents a fundamental weakness in Android's security model's ability to maintain consistent access control enforcement throughout the device's operational lifecycle, particularly during the critical early stages of setup. The vulnerability's exploitation demonstrates the importance of comprehensive security testing during the development phase to identify potential gaps in access control enforcement during system initialization. The security implications of this vulnerability highlight the need for more robust security validation mechanisms that can detect and prevent unauthorized access attempts during the device's most vulnerable periods. The vulnerability's characteristics align with established security principles that require proper state validation before enabling access to sensitive system functions, particularly during the transition from device boot to full operational status. The vulnerability's impact on the Android ecosystem underscores the importance of maintaining consistent security controls throughout all phases of system operation, including the critical setup and initialization stages where device security is most at risk.