CVE-2018-12930 in Linux
Summary
by MITRE
ntfs_end_buffer_async_read in the ntfs.ko filesystem driver in the Linux kernel 4.15.0 allows attackers to trigger a stack-based out-of-bounds write and cause a denial of service (kernel oops or panic) or possibly have unspecified other impact via a crafted ntfs filesystem.
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Analysis
by VulDB Data Team • 03/29/2023
The vulnerability identified as CVE-2018-12930 resides within the ntfs.ko filesystem driver component of the Linux kernel version 4.15.0, specifically in the ntfs_end_buffer_async_read function. This flaw represents a critical stack-based out-of-bounds write condition that can be exploited by malicious actors who craft specially designed ntfs filesystem images. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which encompasses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for kernel-level code execution. The affected kernel version demonstrates a failure in proper bounds checking during asynchronous buffer read operations, creating a pathway for arbitrary code execution or system instability.
The technical implementation of this vulnerability occurs when the ntfs_end_buffer_async_read function processes asynchronous read requests from ntfs filesystems without adequate validation of buffer boundaries. Attackers can construct malicious ntfs filesystem structures that, when mounted or accessed by the vulnerable kernel, trigger the out-of-bounds write condition. The flaw manifests as a stack corruption scenario where the kernel attempts to write data beyond the allocated buffer space, potentially overwriting adjacent stack variables, function return addresses, or other critical kernel memory structures. This condition can result in immediate system termination through kernel oops messages or complete system panics, effectively creating a denial of service scenario that impacts the availability of the affected system.
The operational impact of CVE-2018-12930 extends beyond simple denial of service, as the out-of-bounds write condition could potentially be leveraged for more sophisticated attacks. While the primary effect is system instability and potential crashes, the nature of kernel-level buffer overflows provides opportunities for privilege escalation or arbitrary code execution depending on the specific memory corruption patterns. Systems running the affected kernel version are particularly vulnerable when they process untrusted ntfs filesystems, including those from removable media, network shares, or user-supplied storage devices. The vulnerability affects any Linux system with ntfs support enabled, making it a widespread concern across various deployment scenarios from desktop environments to server infrastructure.
Mitigation strategies for CVE-2018-12930 primarily involve upgrading to a patched kernel version where the ntfs filesystem driver properly validates buffer boundaries during asynchronous read operations. System administrators should prioritize kernel updates to versions that contain the appropriate fixes, typically those released after the vulnerability disclosure. Additionally, implementing filesystem access controls and restricting ntfs mount operations to trusted sources can reduce exposure risk. Organizations should consider disabling ntfs support entirely if the filesystem is not required for operations, as this eliminates the attack surface entirely. Monitoring systems for unusual kernel oops messages or unexpected reboots can help detect exploitation attempts, while network segmentation and access controls should be implemented to limit the potential impact of successful attacks. The vulnerability highlights the importance of kernel security testing and the need for robust input validation in kernel modules to prevent such critical flaws from being exploited in production environments.