CVE-2019-1995 in Android
Summary
by MITRE
In ComposeActivityEmail of ComposeActivityEmail.java, there is a possible way to silently attach files to an email due to a confused deputy. This could lead to local information disclosure, sending files accessible to AOSP Mail to a remote email recipient, with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android. Versions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9. Android ID: A-32589229.
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability described in CVE-2019-1995 represents a critical confused deputy problem within the Android email composition functionality, specifically affecting the ComposeActivityEmail component in the Android Open Source Project mail application. This flaw exists in multiple Android versions including 7.0, 7.1.1, 7.1.2, 8.0, 8.1, and 9.0, indicating a widespread issue that has persisted across several major Android releases. The vulnerability stems from improper permission handling during file attachment operations, creating an attack vector where malicious actors can exploit the system's trust relationships to silently include unauthorized files in email communications.
The technical implementation of this vulnerability occurs within the ComposeActivityEmail.java file where the application fails to properly validate or sanitize file attachment requests. The confused deputy aspect arises because the system incorrectly interprets or forwards file access requests, allowing a malicious process to attach files that should normally be restricted or inaccessible to the email composition context. This flaw operates at the system level where the email application's permission model is bypassed, enabling unauthorized file access and transfer without requiring additional privileges or user interaction. The vulnerability specifically targets the Android OS Mail application's ability to handle file attachments, creating a pathway for information disclosure that leverages the legitimate file access mechanisms of the operating system.
The operational impact of this vulnerability is significant as it enables local information disclosure through silent file attachment capabilities that can be exploited without any user interaction or additional privileges. An attacker can leverage this flaw to automatically attach files from the device to email communications sent to remote recipients, potentially including sensitive or confidential data that should remain protected. The vulnerability affects the fundamental security model of email composition within Android, as it allows unauthorized file access through legitimate application interfaces. This creates a persistent risk where any user with access to the email composition interface can inadvertently or deliberately expose sensitive data through the attachment mechanism, making it particularly dangerous for enterprise environments or users handling confidential information.
The security implications extend beyond simple information disclosure, as this vulnerability can be exploited to create covert data exfiltration channels that bypass normal security controls and user awareness. The attack requires no additional execution privileges, meaning that even standard user accounts can exploit this vulnerability to access and transmit files that would normally be restricted. This vulnerability directly relates to CWE-284, which describes improper access control issues, and aligns with ATT&CK technique T1074.001 for data staging and T1566 for social engineering. The flaw demonstrates a critical failure in Android's permission model during file attachment operations, where the system trusts potentially malicious file access requests without proper verification. Organizations should implement immediate mitigations including system updates, application sandboxing, and network monitoring to detect unauthorized file transfers, while also considering temporary restrictions on email attachment capabilities until full patches are deployed across affected Android versions.
This vulnerability highlights the importance of proper permission validation and access control mechanisms in mobile operating systems, particularly when handling sensitive operations such as file attachment in email applications. The persistent nature of this flaw across multiple Android versions indicates a systemic issue in how the platform handles file access permissions during email composition, requiring comprehensive security reviews of similar components within the Android ecosystem. The lack of user interaction requirements makes this vulnerability particularly concerning for automated exploitation scenarios and emphasizes the need for robust security controls at the operating system level to prevent unauthorized file access and transfer operations.