CVE-2022-3977 in Linux
Summary
by MITRE • 01/12/2023
A use-after-free flaw was found in the Linux kernel MCTP (Management Component Transport Protocol) functionality. This issue occurs when a user simultaneously calls DROPTAG ioctl and socket close happens, which could allow a local user to crash the system or potentially escalate their privileges on the system.
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Analysis
by VulDB Data Team • 02/05/2023
The vulnerability identified as CVE-2022-3977 represents a critical use-after-free flaw within the Linux kernel's Management Component Transport Protocol implementation. This issue specifically manifests in the MCTP subsystem which is designed to facilitate communication between management components in server environments. The flaw arises from improper memory management during concurrent operations involving the DROPTAG ioctl command and socket closure sequences. The vulnerability is particularly concerning as it affects the core kernel networking functionality and can be exploited by local attackers to achieve system compromise.
The technical root cause of this vulnerability stems from a race condition in the MCTP socket implementation where memory allocated to handle DROPTAG operations is freed when a socket is closed, but subsequent operations may still attempt to access this freed memory region. This classic use-after-free condition occurs when multiple kernel threads or processes interact with the same MCTP socket structure without proper synchronization mechanisms. The flaw is categorized under CWE-416 which specifically addresses use-after-free vulnerabilities where memory is accessed after it has been freed, potentially leading to undefined behavior. The vulnerability exists in the kernel's socket management code where the DROPTAG ioctl handler and socket cleanup routines do not properly coordinate their access to shared kernel data structures.
From an operational perspective, this vulnerability presents a significant risk to Linux-based systems that utilize MCTP for management communications, particularly in data center and enterprise server environments. Local attackers with minimal privileges can exploit this flaw to either crash the entire system through kernel panic or potentially escalate their privileges to kernel level access. The attack vector requires local system access but does not need network connectivity, making it particularly dangerous in environments where privilege separation is not properly enforced. The impact extends beyond simple system instability as the privilege escalation capability could allow attackers to gain root access and fully compromise the system. This vulnerability affects all Linux kernel versions that implement MCTP functionality and is particularly concerning given the protocol's use in server management contexts.
The exploitation of this vulnerability aligns with ATT&CK technique T1068 which covers local privilege escalation through kernel vulnerabilities, and T1499 which addresses network denial of service attacks. Organizations should implement immediate mitigations including kernel updates from their distribution vendors, system hardening measures to restrict local access, and monitoring for suspicious kernel activity. The recommended approach involves applying the vendor-provided security patches that address the memory management race condition in the MCTP subsystem. Additionally, system administrators should consider implementing runtime protections such as kernel lockdown modes and privilege separation measures to limit the potential impact of such vulnerabilities. The vulnerability underscores the importance of proper synchronization mechanisms in kernel code and highlights the critical need for thorough testing of concurrent operations in system-level programming.