CVE-2018-16359 in gVisor
Summary
by MITRE
Google gVisor before 2018-08-23, within the seccomp sandbox, permits access to the renameat system call, which allows attackers to rename files on the host OS.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability identified as CVE-2018-16359 represents a critical security flaw in Google gVisor's seccomp sandbox implementation prior to the August 23, 2018 release. This issue specifically affects the container runtime security model that gVisor employs to isolate containerized applications from the host operating system. The seccomp sandbox serves as a crucial security mechanism that restricts system calls available to container processes, thereby preventing unauthorized access to host resources and maintaining the integrity of the underlying infrastructure.
The technical flaw stems from an incomplete system call filtering mechanism within gVisor's seccomp implementation where the renameat system call was inadvertently permitted through the sandbox restrictions. This particular system call allows processes to rename files and directories, but when executed within the context of a compromised container, it can be exploited to manipulate the host filesystem. The renameat system call is particularly dangerous because it enables attackers to rename critical system files, potentially leading to privilege escalation or service disruption. This vulnerability falls under the CWE-264 permission vulnerability category, specifically addressing improper access control within the system call filtering layer.
The operational impact of this vulnerability extends beyond simple file renaming capabilities, as it provides attackers with a means to manipulate the host filesystem in ways that could compromise the entire container infrastructure. An attacker who successfully exploits this vulnerability could rename critical system files, create malicious symbolic links, or even rename files in system directories, potentially leading to complete system compromise. The attack vector typically involves an attacker gaining access to a containerized application and then leveraging the privileged system call access to manipulate host files. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under the T1059 command and script injection and T1068 local privilege escalation tactics, as it enables attackers to execute commands with elevated privileges on the host system.
The mitigation strategy for CVE-2018-16359 involves updating gVisor to version 2018-08-23 or later, which includes the corrected seccomp filtering rules that properly restrict access to the renameat system call. Organizations should also implement comprehensive monitoring of system call patterns and file system modifications to detect potential exploitation attempts. Additionally, container security policies should be reviewed to ensure that only necessary system calls are permitted, and network segmentation should be implemented to limit the potential impact of any successful exploitation. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the necessity of thorough security testing of sandbox mechanisms, particularly those handling system call filtering in containerized environments.