CVE-2022-4378 in Linux
Summary
by MITRE • 01/05/2023
A stack overflow flaw was found in the Linux kernel's SYSCTL subsystem in how a user changes certain kernel parameters and variables. This flaw allows a local user to crash or potentially escalate their privileges on the system.
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Analysis
by VulDB Data Team • 05/18/2025
The vulnerability identified as CVE-2022-4378 represents a critical stack overflow condition within the Linux kernel's SYSCTL subsystem, which governs the dynamic configuration of kernel parameters during runtime. This flaw exists in the kernel's handling of user requests to modify specific kernel variables through the sysctl interface, creating a potential pathway for privilege escalation or system disruption. The vulnerability specifically manifests when user-space applications attempt to modify certain kernel parameters that are processed through the sysctl subsystem, where insufficient bounds checking allows malicious input to overflow the allocated stack buffer. The affected kernel versions typically include those released prior to the patch addressing this issue, making systems running these versions particularly susceptible to exploitation.
The technical implementation of this vulnerability stems from improper input validation within the kernel's sysctl handling code, where user-provided data is directly copied into stack-allocated buffers without adequate size verification. When a local user submits crafted input to modify kernel parameters, the system fails to properly constrain the input length against the buffer boundaries, resulting in memory corruption that can overwrite adjacent stack memory locations. This stack overflow condition can potentially overwrite critical function return addresses or other control data structures, enabling attackers to redirect program execution flow. The vulnerability is classified as a stack-based buffer overflow under CWE-121, which specifically addresses the condition where insufficient bounds checking allows data to overwrite adjacent stack memory. The flaw resides in the kernel's sysctl implementation where the input validation logic fails to properly enforce buffer size limitations during parameter modification operations.
From an operational perspective, this vulnerability presents significant risks to system integrity and availability, as local users with minimal privileges can leverage the flaw to either crash the system through controlled kernel memory corruption or escalate their privileges to root level access. The impact extends beyond simple denial of service, as successful exploitation can provide attackers with complete system control, potentially enabling further lateral movement within network environments or persistence mechanisms. The local privilege escalation aspect of this vulnerability aligns with ATT&CK technique T1068, which covers 'Local Privilege Escalation' through kernel exploits, while the system crash potential maps to T1499.201, covering 'Network Denial of Service' through kernel-level disruptions. The exploitation requires local access and user privileges, making it particularly concerning for environments where untrusted local users exist or where privilege separation is insufficient.
Mitigation strategies for CVE-2022-4378 primarily focus on applying kernel updates and patches released by Linux kernel maintainers, which typically include enhanced bounds checking and input validation mechanisms within the sysctl subsystem. System administrators should prioritize patching affected kernel versions and implement monitoring for unusual sysctl parameter modifications that might indicate exploitation attempts. Additional defensive measures include restricting local user privileges where possible, implementing kernel lockdown mechanisms, and employing kernel module signing to prevent unauthorized kernel code execution. The vulnerability also highlights the importance of kernel hardening techniques such as stack canaries, address space layout randomization, and kernel address space layout randomization to make exploitation more difficult. Organizations should conduct vulnerability assessments to identify systems running vulnerable kernel versions and establish monitoring procedures for detecting anomalous sysctl usage patterns that could indicate attempted exploitation. Regular kernel updates and security audits remain essential practices for maintaining system security posture against similar kernel-level vulnerabilities.