CVE-2017-8267 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, a race condition exists in an IOCTL handler potentially leading to an integer overflow and then an out-of-bounds write.
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Analysis
by VulDB Data Team • 11/09/2019
The vulnerability identified as CVE-2017-8267 represents a critical race condition flaw within the Linux kernel implementation of Qualcomm chips used in Android devices. This issue affects all Qualcomm products that utilize Android releases from the Code Aurora Forum and operates at the kernel level where IOCTL (Input/Output Control) handlers process device-specific commands. The vulnerability stems from improper synchronization mechanisms during the handling of input/output operations, creating a window where concurrent processes can interfere with each other's execution paths.
The technical exploitation of this vulnerability begins with a race condition in the IOCTL handler where multiple threads or processes attempt to access shared resources simultaneously without proper locking mechanisms. This race condition allows an attacker to manipulate the system into performing an integer overflow operation when processing user-supplied data through the IOCTL interface. The integer overflow occurs when the system attempts to calculate buffer sizes or array indices using values that exceed the maximum representable value for the data type, leading to wraparound behavior that can be exploited to control memory access patterns.
The resulting out-of-bounds write vulnerability emerges directly from the integer overflow condition, where the system allocates memory or accesses array elements using calculated values that fall outside the legitimate memory boundaries. This condition allows an attacker to write data to memory locations that should not be accessible, potentially enabling arbitrary code execution or system compromise. The vulnerability is particularly dangerous because it operates at kernel level where privileges are highest, making successful exploitation capable of full system compromise.
From an operational standpoint, this vulnerability affects a broad range of Qualcomm-based Android devices including smartphones, tablets, and other mobile platforms that rely on Qualcomm's Snapdragon processors. The impact extends beyond individual device compromise to potentially affect entire device fleets, especially in enterprise environments where Qualcomm-based devices are prevalent. The vulnerability's exploitation requires minimal privileges and can be triggered through legitimate IOCTL commands, making it particularly insidious as it can be exploited by malicious applications or even system components that normally have trusted access to device drivers.
Security professionals should note this vulnerability aligns with CWE-367, which describes Time-of-Check to Time-of-Use (TOCTOU) race conditions, and represents a specific implementation weakness that can be mapped to ATT&CK technique T1059.007 for command and scripting interpreter. The vulnerability demonstrates the critical importance of proper synchronization mechanisms in kernel code and highlights the need for comprehensive testing of concurrent access scenarios. Mitigation strategies include implementing proper locking mechanisms, validating input parameters before processing, and ensuring integer overflow protection in all IOCTL handler implementations. System administrators should prioritize patch deployment and monitor for exploitation attempts, while developers should adopt secure coding practices that prevent similar race conditions in future implementations.
The broader implications of CVE-2017-8267 underscore the complexity of modern embedded systems security where kernel-level vulnerabilities can have cascading effects across device ecosystems. This vulnerability exemplifies why organizations must maintain robust security practices including regular patch management, kernel hardening, and continuous monitoring of security advisories from vendors like Qualcomm and the Linux kernel community. The vulnerability also demonstrates the necessity of security testing methodologies that specifically target concurrent execution scenarios and race condition detection in kernel code to prevent similar issues from emerging in future implementations.