Understanding CVE-2024-47745: A Recent Linux Kernel Security Vulnerability

Overview of CVE-2024-47745

The CVE-2024-47745 represents a recently published security vulnerability in the Linux kernel. This vulnerability, published on October 21, 2024, potentially allows attackers to bypass a Write XOR Execute (W^X) policy enforced by Security-Enhanced Linux (SELinux). The issue arises due to the improper handling of permissions during the remap_file_pages() syscall, which can lead to security risks when exploited.

Understanding the Vulnerability

At the heart of this issue lies the remap_file_pages syscall handler, which mistakenly calls do_mmap() without performing necessary security checks via the security_mmap_file() Linux Security Module (LSM) hook. This oversight means that when a process triggers personality(READ_IMPLIES_EXEC) and attempts to remap read-write (RW) pages, those pages could inadvertently gain read-write-execute (RWX) permissions. This action effectively bypasses the W^X security enforcement, potentially allowing execution of code that would otherwise be restricted under SELinux.

Impact and Exposure

The exploit risk is categorized under the SSVC framework as having "none" for exploitation, indicating it may not be actively exploited in the wild yet. However, it carries "partial" technical impact, highlighting the potential severity if adversaries develop automated exploits.

Mitigation Strategies

The vulnerability affects specific versions of the Linux kernel, detailed as below:

• Affected Git versions are between 1da177e4c3f4 to 49d3a4ad57c5, 3393fddbfa94, ce14f38d6ee9, and ea7e2d5e49c0.
• Some unaffected versions include custom versions 6.6.54+, 6.10.13+, and 6.11.2+, alongside 6.12-rc1.

To mitigate the vulnerability, users should take the following steps:

• Update the Kernel: Ensure your system is running an unaffected version of the Linux kernel. This is the primary method to shield your system from potential exploits.
• Patch Deployment: Regularly check the kernel repository for available patches that address this issue, specifically those linked to 49d3a4ad57c57227c3b0fd6cd4188b2a5ebd6178, 3393fddbfa947c8e1fdcc4509226905ffffd8b89, ce14f38d6ee9e88e37ec28427b4b93a7c33c70d3, and ea7e2d5e49c05e5db1922387b09ca74aa40f46e2.
• SELinux Policy Review: Reinforce SELinux policies and ensure that custom policies do not inadvertently allow unsafe RWX permissions.

Conclusion

Though the CVE-2024-47745 vulnerability currently has no known exploits, its potential impact should not be underestimated. Proactive mitigation through kernel updates and vigilant security policy management is essential to maintain system integrity and security.