CVE-2018-11023 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 3222560159 and cause a kernel crash.
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Analysis
by VulDB Data Team • 04/02/2020
The vulnerability identified as CVE-2018-11023 resides within the kernel component of Amazon Kindle Fire HD (3rd generation) running Fire OS 4.5.5.3 operating system. This issue manifests in the gcx/gcioctl/gcif.c file which handles device communication through ioctl system calls. The specific flaw occurs when processing ioctl commands directed at the /dev/gcioctl device with command identifier 3222560159, creating a potential pathway for malicious code execution that could compromise the device's kernel integrity.
The technical implementation of this vulnerability stems from inadequate input validation within the ioctl handling mechanism. When an attacker supplies a crafted argument to the ioctl function, the kernel fails to properly sanitize or validate the input parameters before processing them. This lack of proper parameter validation creates a buffer overflow or memory corruption scenario that ultimately results in a kernel crash. The vulnerability represents a classic case of improper input validation that allows attackers to manipulate kernel memory structures through device driver interfaces.
From an operational perspective, this vulnerability presents significant security implications for affected Kindle Fire HD devices. The kernel crash resulting from malicious ioctl arguments effectively renders the device unstable and potentially unusable, creating a denial of service condition that could be exploited by attackers to disrupt device functionality. The vulnerability is particularly concerning because it operates at the kernel level, meaning any successful exploitation could potentially escalate to full system compromise, allowing attackers to execute arbitrary code with kernel privileges.
The vulnerability maps to CWE-121, which describes "Stack-based Buffer Overflow", and also relates to CWE-787, "Out-of-bounds Write", as the improper input handling leads to memory corruption. From an ATT&CK framework perspective, this vulnerability aligns with T1068, "Exploitation for Privilege Escalation", and T1499, "Endpoint Denial of Service", as it enables both privilege escalation and system disruption. The attack surface is limited to devices running the specific Fire OS version and having the affected kernel module loaded, but the impact remains severe due to the kernel-level execution context.
Mitigation strategies should focus on immediate firmware updates from Amazon to patch the vulnerable kernel component. Users should also implement device access controls and monitor for unusual ioctl activity on the affected device. Network-level protections can help detect and prevent exploitation attempts, while system administrators should consider disabling unnecessary device drivers and maintaining strict device access policies. The vulnerability underscores the importance of proper input validation and kernel security hardening practices, particularly in embedded systems where device drivers interact directly with kernel memory structures and lack the extensive security testing applied to desktop operating systems.