CVE-2018-10087 in Linux
Summary
by MITRE
The kernel_wait4 function in kernel/exit.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 by triggering an attempted use of the -INT_MIN value.
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Analysis
by VulDB Data Team • 02/28/2023
The vulnerability identified as CVE-2018-10087 represents a critical denial of service flaw within the Linux kernel's process management subsystem. This issue specifically affects the kernel_wait4 function located in kernel/exit.c and manifests in Linux kernel versions prior to 4.13. The vulnerability arises from an improper handling of negative integer values during process waiting operations, creating a scenario where local attackers can exploit the system's resource management mechanisms to trigger system instability. The flaw is particularly concerning because it operates at the kernel level, meaning that successful exploitation can lead to complete system compromise or unavailability of critical services. The vulnerability's impact is amplified by its local nature, as it requires no network access but can be leveraged by any user with access to the system, making it a significant concern for system administrators and security professionals managing multi-user environments.
The technical root cause of this vulnerability stems from an integer overflow condition that occurs when the kernel_wait4 function processes wait operations for child processes. When an unspecified architecture and compiler combination is used, the function fails to properly validate or handle the -INT_MIN value, which represents the most negative integer that can be represented in a signed 32-bit integer. This particular value creates an edge case in the kernel's process management logic where the system attempts to perform operations that result in undefined behavior or system crashes. The issue is classified under CWE-191 as an Integer Underflow (Wrap or Wraparound) which occurs when a calculation results in a value that is outside the range that can be represented by the data type. The vulnerability demonstrates how seemingly minor arithmetic operations in kernel space can have catastrophic consequences for system stability and availability.
The operational impact of CVE-2018-10087 extends beyond simple denial of service conditions, as it can potentially lead to complete system crashes or reboot cycles that disrupt normal operations. Local users can exploit this vulnerability by triggering specific wait4 system calls that cause the kernel to attempt operations with the -INT_MIN value, resulting in memory corruption or system hang conditions. This vulnerability is particularly dangerous in server environments where continuous uptime is critical, as it can be used to repeatedly crash system services or entire systems without requiring elevated privileges. The attack vector is straightforward and does not require specialized tools or knowledge, making it accessible to a wide range of potential attackers. From an operational security perspective, this vulnerability represents a significant risk to organizations relying on Linux systems, as it can be exploited to create persistent availability issues that may go undetected until system monitoring tools identify the recurring crashes or restarts.
Mitigation strategies for CVE-2018-10087 focus primarily on kernel version upgrades to Linux 4.13 or later, where the vulnerability has been addressed through proper integer validation and handling of edge cases in the wait4 system call implementation. System administrators should prioritize patching affected systems immediately, as the vulnerability provides no privilege escalation capabilities but can be used to cause significant disruption. Additional defensive measures include implementing proper system monitoring to detect unusual restart patterns or kernel panic messages that may indicate exploitation attempts. Organizations should also consider implementing process monitoring tools that can detect abnormal wait4 system call usage patterns, as these may serve as indicators of attempted exploitation. From a compliance standpoint, this vulnerability aligns with various security frameworks and standards that require timely patch management and vulnerability remediation. The ATT&CK framework categorizes this vulnerability under T1499.004 (Endpoint Denial of Service) as it specifically targets system availability through kernel-level exploitation, and the remediation efforts should be integrated into broader security operations center procedures for vulnerability management and incident response protocols.