CVE-2023-4611 in Linux
Summary
by MITRE • 08/30/2023
A use-after-free flaw was found in mm/mempolicy.c in the memory management subsystem in the Linux Kernel. This issue is caused by a race between mbind() and VMA-locked page fault, and may allow a local attacker to crash the system or lead to a kernel information leak.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 09/22/2023
The vulnerability identified as CVE-2023-4611 represents a critical use-after-free flaw within the Linux kernel's memory management subsystem, specifically located in the mm/mempolicy.c file. This flaw manifests as a race condition between the mbind() system call and VMA-locked page fault mechanisms, creating a dangerous window where memory objects can be prematurely freed while still being referenced by active kernel processes. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited by local attackers with minimal privileges to cause system instability or information disclosure. The root cause stems from improper synchronization mechanisms that fail to adequately protect shared kernel data structures during concurrent memory management operations.
The technical implementation of this vulnerability involves a complex interaction between memory policy management and virtual memory area handling within the kernel's memory subsystem. When the mbind() system call attempts to modify memory binding policies while a page fault occurs within a locked virtual memory area, the kernel's memory management code fails to properly handle the race condition. This results in a scenario where a memory allocation is freed from one execution path while another path attempts to access the same memory location, creating the classic use-after-free condition. The flaw is categorized under CWE-416 as a use-after-free vulnerability, which represents one of the most dangerous types of memory corruption flaws due to its potential for arbitrary code execution or system crashes.
Operationally, this vulnerability presents significant risks to system stability and security integrity in environments where multiple processes interact with memory management APIs simultaneously. Local attackers can exploit this condition to cause kernel panics and system crashes, effectively creating a denial-of-service scenario that can bring entire systems down. Additionally, the vulnerability may enable information leakage from kernel memory spaces, potentially exposing sensitive data such as kernel addresses, security credentials, or other confidential information that could be leveraged in more sophisticated attacks. The impact extends beyond simple system instability as it can provide attackers with insights into kernel memory layout and internal structures, making subsequent exploitation attempts more successful.
Mitigation strategies for CVE-2023-4611 should focus on both immediate patching and operational hardening measures. The primary remediation involves applying the latest kernel updates from vendors such as Red Hat, Ubuntu, and other distribution maintainers, as these patches address the race condition through proper synchronization mechanisms and memory management locking. Organizations should prioritize patch deployment across all affected systems, particularly those running kernel versions that are vulnerable to this specific race condition. Additionally, system administrators should implement monitoring solutions to detect unusual memory management patterns that might indicate exploitation attempts, and consider implementing kernel hardening measures such as stack canaries and address space layout randomization to complicate potential exploitation scenarios. The vulnerability's characteristics align with ATT&CK technique T1068 which covers 'Local Privilege Escalation' through kernel exploits, making it a critical target for security operations teams to address promptly.