CVE-2017-8242 in Android
Summary
by MITRE
In all Android releases from CAF using the Linux kernel, a race condition exists in a QTEE driver potentially leading to an arbitrary memory write.
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Analysis
by VulDB Data Team • 12/27/2020
The vulnerability identified as CVE-2017-8242 represents a critical race condition flaw within the Qualcomm TrustZone Execution Environment (QTEE) driver component of Android devices running Linux kernel versions from the Common Android Framework. This vulnerability specifically affects devices that utilize Qualcomm's secure execution environment and exposes a fundamental weakness in how the kernel handles concurrent access to shared memory resources. The race condition occurs during the interaction between the QTEE driver and the underlying kernel subsystems, creating an exploitable scenario where malicious code can manipulate memory locations beyond normal access controls.
The technical flaw manifests as a timing-dependent vulnerability where multiple execution paths can simultaneously access and modify the same memory locations without proper synchronization mechanisms. This race condition allows an attacker to potentially write arbitrary data to memory addresses that should normally be protected or restricted. The vulnerability exists within the driver's implementation of secure memory management functions, where the lack of proper locking mechanisms or atomic operations enables concurrent access patterns that can lead to memory corruption. According to CWE classification, this represents a variant of CWE-362, which specifically addresses race conditions in concurrent programming environments where multiple threads or processes access shared resources without proper synchronization controls.
The operational impact of CVE-2017-8242 extends beyond simple memory corruption, as it provides a potential pathway for privilege escalation and arbitrary code execution within the secure environment. Attackers can exploit this vulnerability to gain unauthorized access to memory regions that should remain protected, potentially allowing them to modify secure kernel components or inject malicious code into the trusted execution environment. This weakness directly violates the fundamental security principles of the TrustZone architecture, which is designed to isolate sensitive operations from the main operating system. The vulnerability's exploitation can lead to complete system compromise, as demonstrated by ATT&CK framework mappings that show how such kernel-level race conditions can be leveraged to establish persistent backdoors and escalate privileges.
Mitigation strategies for CVE-2017-8242 require both immediate patching of affected kernel versions and implementation of proper synchronization mechanisms within the QTEE driver. Organizations should prioritize updating their Android devices to versions that include patches addressing the race condition in the QTEE driver implementation, particularly those that incorporate proper mutex locking or atomic operation usage to prevent concurrent access violations. Additionally, system administrators should implement runtime monitoring for suspicious memory access patterns and consider deploying additional security controls such as kernel module signing verification and secure boot enforcement. The vulnerability highlights the importance of proper concurrent programming practices in kernel space and underscores the need for thorough security testing of driver components, especially those handling secure memory operations. Device manufacturers must also ensure that future implementations of secure execution environments include comprehensive race condition testing and proper synchronization primitives to prevent similar vulnerabilities from emerging in the future.