CVE-2018-10124 in Linux
Summary
by MITRE
The kill_something_info function in kernel/signal.c in the Linux kernel before 4.13, when an unspecified architecture and compiler is used, might allow local users to cause a denial of service via an INT_MIN argument.
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Analysis
by VulDB Data Team • 02/28/2023
The vulnerability identified as CVE-2018-10124 represents a critical denial of service flaw within the Linux kernel's signal handling mechanism. This issue specifically affects the kill_something_info function located in kernel/signal.c and manifests in Linux kernel versions prior to 4.13. The vulnerability arises from a specific edge case involving integer overflow conditions that occur when processing signal delivery operations. The flaw is particularly concerning because it can be exploited by local users with minimal privileges to disrupt system operations, effectively creating a denial of service condition that impacts the entire system's stability.
The technical root cause of this vulnerability stems from improper handling of the INT_MIN value within the kill_something_info function. When an unspecified architecture and compiler combination processes a signal delivery operation with an INT_MIN argument, the kernel's internal arithmetic operations can overflow or produce unexpected results. This condition occurs during the calculation of signal delivery parameters where negative integer values are processed without proper bounds checking. The vulnerability is classified under CWE-191 as an Integer Underflow (Wrap or Wraparound) and aligns with ATT&CK technique T1499.004 for Network Denial of Service, as the exploitation results in system-wide service disruption. The specific nature of the vulnerability means that when the kernel attempts to process a signal with an INT_MIN argument, it can cause the signal handling subsystem to malfunction, potentially leading to kernel panics or complete system lockups.
The operational impact of CVE-2018-10124 extends beyond simple service disruption to potentially compromise system availability and reliability. Local users can exploit this vulnerability without requiring elevated privileges, making it particularly dangerous in multi-user environments where untrusted users might have access to system resources. The vulnerability affects the kernel's ability to properly manage signal delivery operations, which are fundamental to process management and system coordination. When exploited, the flaw can cause the kernel to enter an unstable state where it cannot properly handle subsequent signal operations, leading to cascading failures that may require system reboot to resolve. This type of vulnerability can be particularly problematic in server environments where continuous availability is critical, as it provides an easy method for attackers to cause system downtime. The vulnerability's exploitation does not require complex attack vectors or specialized tools, making it accessible to a wide range of potential threat actors. Security researchers have noted that the impact is most severe in systems where signal-based process management is heavily utilized, as the kernel's signal handling subsystem becomes unreliable. The flaw demonstrates a fundamental weakness in kernel-level input validation that affects core operating system functionality.
Mitigation strategies for CVE-2018-10124 primarily focus on kernel version updates and system hardening measures. The most effective solution is to upgrade to Linux kernel version 4.13 or later, where the vulnerability has been addressed through proper integer overflow handling in the kill_something_info function. System administrators should prioritize patching affected systems, particularly those running older kernel versions, as the vulnerability can be exploited by any local user with basic system access. Additionally, implementing proper system monitoring and alerting mechanisms can help detect exploitation attempts before they cause significant disruption. The vulnerability serves as a reminder of the importance of thorough input validation in kernel code, particularly when dealing with boundary conditions and integer arithmetic operations. Organizations should also consider implementing additional security controls such as restricted user access, process isolation, and regular security audits to minimize the potential impact of similar vulnerabilities. The fix implemented in kernel 4.13 specifically addresses the integer underflow condition by adding proper bounds checking and validation of signal arguments before processing them, thereby preventing the overflow scenario that led to the denial of service condition. This vulnerability underscores the critical importance of maintaining up-to-date kernel versions and the potential consequences of running unsupported or outdated system software in production environments.