CVE-2014-9936 in Android
Summary
by MITRE
In TrustZone a time-of-check time-of-use race condition could potentially exist in an authentication routine in all Android releases from CAF using the Linux kernel.
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Analysis
by VulDB Data Team • 12/24/2020
The vulnerability identified as CVE-2014-9936 represents a critical time-of-check time-of-use race condition within the TrustZone security architecture of Android devices. This flaw exists in the authentication routines implemented in Qualcomm Android Framework (CAF) using the Linux kernel, affecting all Android releases that utilize this framework. The race condition occurs when the system performs a check operation followed by a use operation that could potentially be exploited by malicious actors to bypass authentication mechanisms.
This vulnerability operates at the intersection of hardware and software security layers, specifically targeting the secure element within TrustZone architecture. The flaw arises from the timing gap between when a system validates access permissions and when it actually executes the authenticated operation. During this window, an attacker could manipulate the system state to exploit the race condition, potentially gaining unauthorized access to protected resources or functionalities. The vulnerability is particularly concerning because it affects the fundamental authentication mechanisms that protect sensitive system components and user data.
The operational impact of CVE-2014-9936 extends beyond simple authentication bypasses, as it could enable attackers to escalate privileges and gain access to confidential information stored within the secure environment. This race condition could allow malicious applications to circumvent the security controls designed to protect sensitive operations, potentially leading to full system compromise. The vulnerability affects devices running Android versions that implement Qualcomm's CAF framework, making it widespread across numerous mobile devices and tablets that utilize Qualcomm processors.
Security implications of this vulnerability align with CWE-367, which addresses time-of-check to time-of-use race conditions, and can be mapped to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation." The vulnerability represents a classic example of how hardware security features can be undermined by software implementation flaws, particularly in complex security architectures like TrustZone that rely on precise timing and state management. Mitigation strategies should focus on implementing proper synchronization mechanisms, reducing the time window between check and use operations, and ensuring that authentication routines are designed to be atomic and resistant to timing attacks.
The vulnerability highlights the challenges in securing complex embedded systems where hardware security features interact with software implementations. Device manufacturers should ensure that all authentication routines are properly synchronized and that race conditions are eliminated through proper code design and security testing. Regular security audits of TrustZone implementations and authentication mechanisms are essential to prevent exploitation of similar vulnerabilities in the future. The flaw demonstrates the critical importance of considering timing attacks and race conditions in security design, particularly for systems that rely on hardware security modules and secure enclaves for protection of sensitive operations.