CVE-2023-40134 in Android
Summary
by MITRE • 10/28/2023
In isFullScreen of FillUi.java, there is a possible way to view another user's images due to a confused deputy. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 11/19/2023
The vulnerability identified as CVE-2023-40134 resides within the FillUi.java file in the isFullScreen method, representing a confused deputy problem that enables unauthorized access to user data. This type of vulnerability occurs when a system component incorrectly handles requests from one user while acting on behalf of another, creating a security boundary violation that allows information disclosure. The flaw specifically manifests in the context of fullscreen functionality where the application fails to properly validate or authenticate user contexts before granting access to image resources. The vulnerability is classified as a confused deputy issue under CWE-289, which describes situations where a program or service acts as an intermediary for one entity while performing operations on behalf of another, leading to privilege escalation or unauthorized data access. This particular implementation flaw allows an attacker to potentially view another user's images without requiring any additional privileges or user interaction, making it particularly concerning from a security perspective.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a fundamental breakdown in access control mechanisms within the application's user interface layer. Attackers can exploit this vulnerability to gain unauthorized access to sensitive visual content belonging to other users, potentially exposing personal photos, documents, or other image-based data that should remain private. The lack of user interaction requirement for exploitation means that the vulnerability can be leveraged automatically without any social engineering or additional attack vectors. This type of local information disclosure threat directly violates the principle of least privilege and can lead to privacy violations, data breaches, and potential identity theft if the compromised images contain sensitive personal information. The vulnerability's classification under ATT&CK technique T1005 suggests it could be used as part of broader reconnaissance or data collection activities within a compromised system.
Mitigation strategies for CVE-2023-40134 should focus on implementing robust authentication and authorization checks within the isFullScreen method and related UI components. The solution requires ensuring that all requests for image resources are properly validated against the requesting user's context and permissions before granting access. Developers should implement proper session management and user context validation mechanisms that prevent the confused deputy scenario from occurring. This includes adding explicit checks to verify that the current user context matches the resource owner before allowing access to image data. Security measures should also include input validation and proper access control enforcement at the application layer, ensuring that even if a user attempts to access another user's resources, the system properly rejects such requests. Additionally, implementing proper logging and monitoring of access attempts can help detect and respond to potential exploitation attempts, while regular security code reviews should be conducted to identify similar confused deputy vulnerabilities in other parts of the application codebase.