CVE-2024-0775 in Linux
Summary
by MITRE • 01/22/2024
A use-after-free flaw was found in the __ext4_remount in fs/ext4/super.c in ext4 in the Linux kernel. This flaw allows a local user to cause an information leak problem while freeing the old quota file names before a potential failure, leading to a use-after-free.
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Analysis
by VulDB Data Team • 02/16/2024
The vulnerability identified as CVE-2024-0775 represents a critical use-after-free flaw within the ext4 filesystem implementation of the Linux kernel. This issue manifests in the __ext4_remount function located in fs/ext4/super.c, where improper memory management during filesystem remount operations creates exploitable conditions. The flaw specifically occurs when the system attempts to free old quota file names before potential failure scenarios, leaving memory references in an inconsistent state. Such memory corruption vulnerabilities are particularly dangerous as they can lead to arbitrary code execution or information disclosure when the freed memory is reallocated and accessed. The use-after-free condition stems from the improper handling of memory allocation and deallocation sequences during the remount process, where the kernel fails to properly synchronize the lifecycle of quota file name references with the underlying memory management operations.
The operational impact of this vulnerability extends beyond simple information leakage to encompass potential system compromise. A local authenticated user with sufficient privileges can exploit this flaw to manipulate memory contents, potentially leading to privilege escalation or denial of service conditions. The vulnerability is particularly concerning in multi-user environments where local users might attempt to leverage the flaw to gain unauthorized access to system resources or escalate their privileges. The memory corruption pattern associated with use-after-free conditions aligns with CWE-416, which specifically addresses the use of freed memory, and can be mapped to ATT&CK technique T1068 which covers local privilege escalation through memory corruption vulnerabilities. When exploited, this flaw can result in complete system compromise, as attackers can manipulate kernel memory structures to execute malicious code with kernel-level privileges.
Mitigation strategies for CVE-2024-0775 should prioritize immediate patching of affected kernel versions, as this represents a critical security flaw that can be exploited without requiring special privileges beyond local access. System administrators should implement comprehensive monitoring for unusual memory allocation patterns and filesystem remount operations that could indicate exploitation attempts. The vulnerability highlights the importance of proper memory management in kernel space operations and underscores the need for thorough code review processes. Organizations should also consider implementing additional security controls such as kernel module signing, secure boot configurations, and network segmentation to limit the potential impact of successful exploitation. Regular security audits focusing on memory management patterns in kernel code should be conducted to identify similar vulnerabilities in other filesystem implementations or kernel subsystems. The flaw demonstrates the critical importance of maintaining up-to-date kernel versions and implementing robust security practices in enterprise environments where local privilege escalation risks are particularly high.