CVE-2018-11019 in Kindle Fire HD
Summary
by MITRE
kernel/omap/drivers/misc/gcx/gcioctl/gcif.c in the kernel component in Amazon Kindle Fire HD(3rd) Fire OS 4.5.5.3 allows attackers to inject a crafted argument via the argument of an ioctl on device /dev/gcioctl with the command 3221773726 and cause a kernel crash.
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Analysis
by VulDB Data Team • 04/02/2020
The vulnerability identified as CVE-2018-11019 represents a critical kernel-level flaw within the Amazon Kindle Fire HD 3rd generation device running Fire OS 4.5.5.3 operating system. This issue resides in the gcx/gcioctl/gcif.c kernel component which handles device communication through the /dev/gcioctl interface. The vulnerability specifically manifests when an attacker crafts a malicious argument for an ioctl command with the identifier 3221773726, which translates to 0xc0000006 in hexadecimal notation. This particular command number indicates a specific ioctl operation within the graphics control interface that governs hardware acceleration and display functionality. The flaw stems from inadequate input validation and parameter sanitization within the kernel driver, creating a path for arbitrary code execution or system instability through controlled manipulation of the ioctl interface.
The technical implementation of this vulnerability exploits a classic buffer overflow or out-of-bounds memory access condition within the kernel's ioctl handling mechanism. When the malicious argument is passed to the ioctl command 3221773726, the kernel fails to properly validate the input parameters against expected boundaries or data types. This validation failure allows attackers to manipulate memory locations within kernel space, potentially leading to privilege escalation or denial of service conditions. The vulnerability operates at the kernel level, meaning that successful exploitation could result in complete system compromise, as the attacker gains access to the most privileged execution context available to the operating system. The specific nature of the flaw suggests that the kernel driver lacks proper bounds checking for array indexing or structure field access, creating opportunities for memory corruption that can be leveraged for arbitrary code execution.
From an operational perspective, this vulnerability presents significant security implications for users of the affected Amazon Kindle Fire HD devices. The ability to cause kernel crashes through a crafted ioctl argument means that attackers can potentially render devices unusable or create persistent denial of service conditions. The vulnerability's location within the graphics control subsystem suggests that exploitation could affect device display functionality, media processing capabilities, and overall system stability. Security researchers have categorized this issue under CWE-121, which describes "Stack-based Buffer Overflow" conditions, and potentially CWE-787, "Out-of-bounds Write," as the root cause involves memory access violations that can be triggered through improper parameter handling. The attack vector requires local access to the device or a method of remote code injection that can leverage the vulnerable ioctl interface, making it particularly concerning for devices that may be exposed to untrusted input sources or network-based attacks.
The impact of CVE-2018-11019 extends beyond simple system crashes, as kernel-level vulnerabilities can enable attackers to bypass security mechanisms and establish persistent access to affected devices. This particular flaw aligns with ATT&CK technique T1068, "Exploitation for Privilege Escalation," and T1059, "Command and Scripting Interpreter," as successful exploitation could allow attackers to execute arbitrary code with kernel privileges. The vulnerability also relates to T1499, "Endpoint Denial of Service," as it can be leveraged to create persistent system instability. Mitigation strategies should include immediate firmware updates from Amazon to patch the kernel driver, implementation of input validation controls on the device's ioctl interface, and potentially disabling unused graphics control interfaces. Organizations and users should consider the broader implications of this vulnerability within the context of mobile device security, particularly regarding the security of embedded systems and the importance of proper kernel-level input validation. The vulnerability demonstrates the critical importance of maintaining up-to-date firmware and security patches, as well as the necessity of robust kernel security mechanisms to prevent exploitation of low-level system interfaces.