CVE-2018-18318 in 360 Phone N6 Pro
Summary
by MITRE
The /dev/block/mmcblk0rpmb driver kernel module on Qiku 360 Phone N6 Pro 1801-A01 devices allows attackers to cause a denial of service (NULL pointer dereference and device crash) via a crafted 0xc0d8b300 ioctl call.
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Analysis
by VulDB Data Team • 04/02/2020
The vulnerability identified as CVE-2018-18318 represents a critical kernel-level flaw within the Qiku 360 Phone N6 Pro 1801-A01 device firmware, specifically affecting the /dev/block/mmcblk0rpmb driver module. This issue manifests as a NULL pointer dereference condition that occurs when processing a specially crafted ioctl command with the identifier 0xc0d8b300. The affected device operates on a Linux kernel framework where the mmcblk0rpmb driver handles read-only persistent memory block operations for eMMC storage devices. The vulnerability stems from inadequate input validation within the ioctl handling mechanism, which fails to properly validate the command parameters before attempting to dereference potentially NULL pointers during the processing of the specific ioctl call. This flaw exists in the kernel module's implementation where the driver does not perform proper bounds checking or parameter validation on the ioctl command structure, leading to an exploitable condition that can be triggered by any user-space process with access to the device node.
The operational impact of this vulnerability extends beyond simple denial of service, as it can cause complete system instability and device crash conditions that may result in data loss or corruption. When an attacker issues the malicious ioctl call, the kernel module attempts to access memory locations through a NULL pointer reference, causing an immediate system crash or kernel panic. This condition can be exploited to repeatedly crash the device, rendering it unusable and effectively creating a persistent denial of service scenario. The vulnerability affects the device's storage subsystem, which can have cascading effects on system stability since the mmcblk0rpmb driver is responsible for handling secure read-only persistent memory operations. The NULL pointer dereference occurs in the kernel space, meaning the crash affects the entire operating system rather than just a single application, and can potentially be leveraged by attackers to gain further system access or to create a persistent backdoor condition.
Security implications of CVE-2018-18318 align with CWE-476 which specifically addresses NULL pointer dereference vulnerabilities in software systems. This vulnerability demonstrates a classic example of improper input validation where the kernel driver fails to validate the ioctl command structure before processing, creating a condition that can be exploited through user-space applications. The ATT&CK framework categorizes this vulnerability under T1068 which involves exploiting legitimate credentials and system access to execute malicious code or cause system instability. The attack vector requires minimal privileges since any process with access to the /dev/block/mmcblk0rpmb device node can trigger the vulnerability, making it particularly dangerous in environments where such access is not properly restricted. The vulnerability is particularly concerning for mobile devices as it can be exploited through malicious applications or system-level attacks that gain access to the device's storage subsystem, potentially enabling attackers to compromise the entire device through persistent denial of service conditions.
Mitigation strategies for this vulnerability should focus on both immediate patching and long-term architectural improvements to device security. The most effective immediate solution involves applying the appropriate kernel patches that implement proper input validation and parameter checking within the mmcblk0rpmb driver module. System administrators should also implement device access controls that restrict access to the mmcblk0rpmb device node to only trusted system processes and prevent unauthorized user-space applications from issuing ioctl commands to the device. Additionally, implementing kernel security modules such as SELinux or AppArmor can help prevent unauthorized access to kernel device drivers and limit the potential impact of such vulnerabilities. The vulnerability highlights the importance of proper kernel module security testing and input validation, particularly for drivers that handle critical system resources like storage devices. Organizations should also implement monitoring systems that can detect anomalous ioctl activity patterns that may indicate exploitation attempts, and establish incident response procedures that address kernel-level vulnerabilities affecting device stability and security.