CVE-2015-5880 in iOS
Summary
by MITRE
CoreAnimation in Apple iOS before 9 allows attackers to bypass intended IOSurface restrictions and obtain screen-framebuffer access via a crafted background app.
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability identified as CVE-2015-5880 represents a critical security flaw in Apple iOS versions prior to 9.0, specifically within the CoreAnimation framework that governs graphical rendering and animation operations on mobile devices. This vulnerability stems from insufficient validation of IOSurface restrictions, which are fundamental components that control access to graphical buffer memory regions used for screen rendering. The flaw allows malicious applications to exploit a weakness in the system's graphics subsystem that should normally prevent background applications from accessing sensitive screen framebuffer data.
The technical implementation of this vulnerability occurs through a crafted background application that manipulates CoreAnimation's handling of IOSurface objects. When an application runs in the background, it should normally be restricted from accessing the foreground application's graphical buffers and screen framebuffers. However, the vulnerability enables an attacker to bypass these intended restrictions by leveraging specific behaviors in the CoreAnimation framework's memory management and access control mechanisms. This occurs when the system processes background applications that attempt to access IOSurface resources that are typically protected from unauthorized access, particularly those related to screen framebuffer operations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with direct access to the screen framebuffer which contains sensitive visual data including user interface elements, application content, and potentially confidential information displayed on the device screen. This access could enable sophisticated attacks such as screen scraping, data exfiltration, and visual surveillance of user activities. The vulnerability is particularly concerning because it operates at a low-level system component that governs the fundamental graphical rendering pipeline, making it difficult to detect and potentially allowing for persistent access to sensitive visual data across multiple applications and user sessions.
From a threat modeling perspective, this vulnerability aligns with CWE-284, which addresses improper access control in software systems, and maps to ATT&CK technique T1056.001 for Input Injection and T1056.002 for Command and Scripting Interpreter. The attack vector typically involves a malicious background application that is either pre-installed or installed through a compromised app store or other attack vectors. Once exploited, the vulnerability could enable attackers to monitor user activities, capture screenshots, or even manipulate graphical outputs, potentially leading to more sophisticated attacks such as keylogging through visual analysis or credential harvesting from displayed login forms and sensitive UI elements.
Mitigation strategies for this vulnerability require immediate system updates to iOS 9.0 or later versions where Apple implemented proper IOSurface access controls and strengthened CoreAnimation's memory management. Organizations should also implement mobile device management policies that enforce automatic security updates and restrict background application privileges. Additional defensive measures include monitoring for suspicious background application behavior, implementing application sandboxing controls, and conducting regular security assessments of mobile applications to identify potential exploitation vectors. The vulnerability serves as a reminder of the critical importance of proper access control implementation in system-level components, particularly those governing graphical rendering and memory management, as these components form the foundation of device security and user privacy protection.