CVE-2015-8998 in Android
Summary
by MITRE
In TrustZone an integer overflow vulnerability can potentially occur 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-2015-8998 represents a critical integer overflow flaw within the TrustZone security architecture of Android devices. This issue affects all Android releases that utilize the Linux kernel and are developed by the Code Aurora Forum, creating a widespread impact across numerous mobile devices. TrustZone serves as a hardware-based security subsystem that provides a secure environment for processing sensitive operations, making this vulnerability particularly concerning for mobile security implementations.
The technical flaw manifests as an integer overflow condition that can occur in the TrustZone component during specific kernel operations. When processing certain data inputs, the system fails to properly validate integer values, leading to situations where arithmetic operations exceed the maximum representable value for the data type. This overflow condition can result in unpredictable behavior, memory corruption, or potentially allow privilege escalation within the secure execution environment. The vulnerability specifically affects the kernel-level implementation where TrustZone interacts with the main operating system, creating a pathway for exploitation that bypasses normal security boundaries.
The operational impact of this vulnerability extends beyond simple system instability, as it can potentially enable attackers to gain unauthorized access to the secure world of TrustZone. This environment typically handles sensitive operations such as cryptographic key management, secure boot processes, and authentication mechanisms. An attacker who successfully exploits this integer overflow could potentially execute arbitrary code within the secure environment, undermining the fundamental security guarantees that TrustZone is designed to provide. The vulnerability's presence in all Android releases from CAF means that a vast number of devices remain at risk, particularly those in the mobile device ecosystem where TrustZone is actively utilized for security purposes.
Mitigation strategies for CVE-2015-8998 require immediate patching of affected kernel versions and implementation of proper input validation mechanisms within TrustZone components. Organizations should prioritize updating their Android devices to versions that include fixed kernel implementations, while also implementing monitoring for anomalous behavior that might indicate exploitation attempts. The vulnerability aligns with CWE-190, which addresses integer overflow conditions, and represents a significant concern for the ATT&CK framework's privilege escalation techniques. Security teams should also consider implementing additional runtime protections and memory corruption defenses to reduce the attack surface, while maintaining awareness of potential indirect exploitation vectors that might leverage this vulnerability in combination with other security flaws.
This vulnerability demonstrates the critical importance of secure coding practices within kernel-level components, particularly those that interface with security-sensitive hardware subsystems. The integer overflow condition highlights the need for comprehensive testing of boundary conditions and proper validation of all arithmetic operations, especially in environments where security is paramount. Mobile device manufacturers and security researchers must continue to prioritize thorough code review processes for kernel components to prevent similar issues from emerging in future implementations. The widespread nature of this vulnerability across CAF-based Android releases underscores the necessity for coordinated security updates and the importance of maintaining up-to-date security practices throughout the mobile ecosystem.