CVE-2022-2590 in Linux
Summary
by MITRE • 08/31/2022
A race condition was found in the way the Linux kernel's memory subsystem handled the copy-on-write (COW) breakage of private read-only shared memory mappings. This flaw allows an unprivileged, local user to gain write access to read-only memory mappings, increasing their privileges on the system.
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Analysis
by VulDB Data Team • 10/10/2022
The vulnerability identified as CVE-2022-2590 represents a critical race condition within the Linux kernel's memory management subsystem that specifically targets the copy-on-write mechanism used for shared memory mappings. This flaw exists in the kernel's handling of private read-only shared memory mappings where the system fails to properly synchronize access during the copy-on-write breakage process. The race condition occurs when multiple threads or processes attempt to access the same memory mapping simultaneously, creating a temporal window where the kernel's memory management logic does not adequately prevent concurrent modifications to the same memory region. This vulnerability is particularly dangerous because it allows local users to escalate their privileges through a technique that exploits the fundamental memory protection mechanisms designed to prevent unauthorized write access to read-only memory segments.
The technical implementation of this vulnerability stems from improper synchronization within the kernel's memory management code that governs how copy-on-write operations are handled when a process attempts to modify a shared read-only memory mapping. When a process tries to write to what should be read-only memory, the kernel typically triggers a copy-on-write operation that creates a private copy of the memory page for that specific process. However, due to the race condition in the kernel's memory subsystem, there exists a brief period during which the memory mapping can be modified by another process or thread before the copy-on-write mechanism fully completes. This temporal inconsistency allows an unprivileged user to gain write access to memory regions that should remain read-only, effectively bypassing the kernel's memory protection mechanisms.
The operational impact of CVE-2022-2590 is significant as it provides a local privilege escalation vector that can be exploited by any user with access to the system. The vulnerability does not require special privileges or network access, making it particularly dangerous in multi-user environments where users might attempt to exploit this weakness to gain elevated system privileges. Attackers can leverage this vulnerability to execute arbitrary code with kernel-level privileges, potentially leading to complete system compromise. The flaw affects systems running Linux kernel versions where the race condition exists in the memory management subsystem, and it can be exploited to bypass security controls such as read-only memory protections, potentially allowing attackers to modify critical system components, inject malicious code, or establish persistent backdoors. This vulnerability directly relates to CWE-362, which describes race conditions in concurrent programming, and can be mapped to ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' in the adversary tactics framework.
Mitigation strategies for CVE-2022-2590 primarily involve applying the appropriate kernel security patches released by the Linux kernel maintainers and system vendors. Organizations should prioritize updating their systems to kernel versions that contain the fix for this race condition, which typically involves implementing proper synchronization mechanisms during copy-on-write operations. System administrators should also consider implementing additional security controls such as disabling unnecessary shared memory mappings, monitoring for suspicious memory access patterns, and employing kernel hardening techniques like stack canaries and memory protection mechanisms. The vulnerability underscores the importance of maintaining up-to-date kernel versions and implementing robust memory management security practices. Additionally, organizations should conduct thorough security assessments to identify systems potentially affected by this vulnerability and implement monitoring solutions that can detect unusual memory access patterns that might indicate exploitation attempts. Regular security audits and vulnerability assessments should include checks for similar race conditions in other kernel subsystems to prevent similar vulnerabilities from being exploited in the future.