CVE-2017-6274 in Android
Summary
by MITRE
An elevation of Privilege vulnerability exists in the Thermal Driver, where a missing bounds checks in the thermal throttle driver can cause an out-of-bounds write in the kernel. This issue is rated as moderate. Product: Pixel. Version: N/A. Android ID: A-34705801. References: N-CVE-2017-6274.
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Analysis
by VulDB Data Team • 12/06/2019
The vulnerability identified as CVE-2017-6274 represents a critical security flaw within the Android kernel's thermal management subsystem, specifically affecting the thermal throttle driver component. This issue manifests as a missing bounds check that creates an exploitable condition allowing for out-of-bounds memory writes during kernel execution. The vulnerability was particularly concerning as it affected the Pixel line of devices, making them susceptible to privilege escalation attacks that could potentially compromise the entire operating system. The thermal driver is responsible for managing system temperature through various cooling mechanisms including CPU frequency throttling and fan control, making it a critical component in the device's power management architecture.
The technical implementation of this vulnerability stems from inadequate input validation within the thermal throttle driver's kernel code. When the driver processes thermal events or temperature readings, it fails to properly validate the bounds of memory accesses, creating a scenario where malicious input could cause the kernel to write data beyond the allocated memory boundaries. This type of flaw falls under the CWE-129 category of "Improper Validation of Array Index" and represents a classic buffer overflow condition that can be exploited to gain elevated privileges within the kernel space. The missing bounds check essentially removes the protective mechanisms that would normally prevent memory corruption during array or buffer operations, allowing attackers to manipulate kernel memory directly.
From an operational perspective, this vulnerability poses significant risks to device security and user privacy. An attacker with local access to a vulnerable Pixel device could exploit this condition to escalate privileges from a regular user context to kernel-level privileges, effectively bypassing all Android security mechanisms including SELinux policies, application sandboxing, and other mandatory access controls. The impact extends beyond simple privilege escalation as kernel-level access provides complete control over device functions including the ability to modify system files, access encrypted data, monitor network traffic, and potentially install persistent backdoors. This vulnerability directly aligns with ATT&CK technique T1068 which describes "Exploitation for Privilege Escalation" and represents a critical attack surface for adversaries seeking to establish persistent access to mobile devices.
The mitigation strategies for CVE-2017-6274 primarily involve applying the appropriate security patches and kernel updates provided by Google and device manufacturers. Android Security Bulletins typically address such vulnerabilities through kernel-level fixes that implement proper bounds checking mechanisms and memory validation routines. Organizations and users should ensure that all Pixel devices receive the relevant security updates promptly, as the window of exploitation remains open until patches are applied. Additionally, network administrators should monitor for potential exploitation attempts and implement network-based detection measures that can identify anomalous behavior patterns consistent with privilege escalation attacks. The vulnerability highlights the importance of comprehensive kernel security testing and the need for robust input validation mechanisms in all system components that handle external or untrusted data inputs.