CVE-2016-3896 in Android
Summary
by MITRE
AOSP Mail 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 2016-09-01 allows attackers to obtain sensitive EmailAccountCacheProvider information via a crafted application, aka internal bug 29767043.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability identified as CVE-2016-3896 represents a critical information disclosure flaw within the Android Open Source Project Mail application across multiple versions of the Android operating system. This security weakness affects Android versions 4.x prior to 4.4.4, 5.0.x prior to 5.0.2, 5.1.x prior to 5.1.1, and 6.x prior to the specified date of 2016-09-01. The vulnerability specifically resides in the EmailAccountCacheProvider component which serves as a data storage mechanism for email account information within the Android email client framework.
The technical implementation of this vulnerability stems from insufficient access controls and improper input validation within the EmailAccountCacheProvider interface. Attackers can exploit this weakness by crafting a malicious application that directly interacts with the vulnerable provider component through Android's inter-process communication mechanisms. The flaw allows unauthorized applications to bypass normal access restrictions and retrieve cached email account information, including potentially sensitive credentials and account details that should remain protected within the system's secure boundaries. This represents a classic case of inadequate privilege separation and insufficient sandboxing controls within the Android email application architecture.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential pathways for credential theft and identity compromise. When malicious applications can access cached email account information, they gain access to authentication tokens, server configurations, and potentially user credentials that could be leveraged for further attacks. This vulnerability particularly affects enterprise environments where Android devices may contain corporate email accounts with access to sensitive business data, making it a significant concern for organizations implementing mobile device management strategies. The vulnerability aligns with CWE-200, which addresses "Information Exposure," and represents a failure in proper access control mechanisms that should prevent unauthorized data access.
From an attacker's perspective, this vulnerability fits within the ATT&CK framework under the technique T1552, "Unsecured Credentials," as it enables unauthorized access to stored email account information without requiring additional authentication factors. The exploitation process involves installing a malicious application that can leverage Android's content provider access mechanisms to query the EmailAccountCacheProvider directly. This attack vector demonstrates the importance of proper Android security model implementation and highlights the risks associated with insufficient inter-application security boundaries. Organizations should consider this vulnerability as part of broader mobile security assessments, particularly when evaluating email client security in mobile device management programs.
The mitigation strategy for this vulnerability involves applying the appropriate security patches and updates released by Google for the affected Android versions. System administrators should ensure that all Android devices are updated to versions that include the fix for this specific vulnerability, which typically involves strengthening access controls and implementing proper input validation within the EmailAccountCacheProvider component. Additionally, organizations should implement mobile threat defense measures including application whitelisting, regular security scanning of installed applications, and monitoring for suspicious behavior patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date mobile operating systems and the potential consequences of neglecting security updates in mobile environments.