CVE-2016-2425 in Android
Summary
by MITRE
mail/compose/ComposeActivity.java in 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 2016-04-01 supports file:///data attachments, which allows attackers to obtain sensitive information via a crafted application, aka internal bugs 7154234 and 26989185.
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Analysis
by VulDB Data Team • 07/12/2022
The vulnerability described in CVE-2016-2425 represents a critical security flaw in the Android email application's handling of file attachments within the AOSP Mail component. This issue affects multiple Android versions including 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before the specified date, creating a widespread impact across the Android ecosystem. The vulnerability specifically resides in the ComposeActivity.java file which processes email composition and attachment handling functionality, making it a core component of the email application's security architecture.
The technical flaw stems from the improper validation of file attachment URIs within the email composition interface. When the Android Mail application processes email attachments, it fails to adequately sanitize or restrict the file:// URI scheme that allows access to internal application data directories. This oversight enables malicious applications to craft specially designed email compositions that reference files within the target application's private data directory using the file:///data/ scheme. The vulnerability essentially creates an information disclosure pathway where unauthorized access to sensitive internal data can occur through crafted email attachments.
From an operational impact perspective, this vulnerability allows attackers to extract sensitive information from the email application's private storage space, potentially including email content, account credentials, contact information, and other confidential data stored within the application's private data directories. The attack vector is particularly concerning because it requires only a crafted malicious application to exploit the vulnerability, making it accessible to threat actors without requiring elevated privileges or complex attack chains. The vulnerability's classification under CWE-22 indicates a weakness in improper limitation of a pathname to a restricted directory, while its exploitation aligns with ATT&CK technique T1059.001 for command and scripting interpreter execution.
The security implications extend beyond simple information disclosure as attackers can potentially access not just email content but also sensitive metadata and application-specific data that may be stored in the application's private storage areas. This includes potentially sensitive user information, application configuration data, and other private data that should remain isolated from unauthorized access. The vulnerability's presence in multiple Android versions demonstrates the persistence of such security flaws and the importance of proper input validation in mobile application development. Organizations and users affected by this vulnerability should implement immediate mitigations including applying the relevant Android security patches, updating to supported Android versions, and implementing network-level monitoring to detect suspicious email attachment behavior. The vulnerability also highlights the importance of proper URI handling and access control mechanisms in mobile application development, particularly when dealing with file system access and inter-application communication.