CVE-2019-2389 in MongoDB
Summary
by MITRE
Incorrect scoping of kill operations in MongoDB Server's packaged SysV init scripts allow users with write access to the PID file to insert arbitrary PIDs to be killed when the root user stops the MongoDB process via SysV init. This issue affects: MongoDB Inc. MongoDB Server v4.0 versions prior to 4.0.11; v3.6 versions prior to 3.6.14; v3.4 versions prior to 3.4.22.
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Analysis
by VulDB Data Team • 12/11/2023
This vulnerability resides in the MongoDB Server's SysV init scripts where improper scoping of kill operations creates a privilege escalation path. The flaw manifests when users with write access to the PID file can manipulate the process identifier to inject arbitrary PIDs that will be terminated when the root user executes the stop command through SysV init. This represents a classic privilege escalation vulnerability where unprivileged users can leverage write permissions on a system file to execute arbitrary commands with elevated privileges. The vulnerability stems from insufficient validation of the PID file contents before processing kill operations, creating a path where malicious actors can redirect kill signals to unintended processes. The issue affects multiple MongoDB server versions including 4.0.x prior to 4.0.11, 3.6.x prior to 3.6.14, and 3.4.x prior to 3.4.22, indicating this was a widespread concern across MongoDB's major release lines. The vulnerability aligns with CWE-276 which describes improper privileges and CWE-78 which covers OS command injection, both of which are exploited through the manipulation of system process management files.
The operational impact of this vulnerability extends beyond simple privilege escalation as it allows attackers to potentially disrupt critical MongoDB services or even target other system processes. When the root user stops the MongoDB service, the init script reads the PID file and attempts to kill all processes listed within it, without proper validation of the process identifiers. This creates an opportunity for attackers to insert PIDs of other running processes, potentially causing service disruption or even system instability. The attack vector requires only write access to the PID file, which may be accessible through various means including compromised user accounts or misconfigured file permissions. This vulnerability directly maps to ATT&CK technique T1068 which describes local privilege escalation through the exploitation of system-level vulnerabilities, and T1489 which covers service stoppage through manipulation of system processes.
Mitigation strategies for this vulnerability involve both immediate patching and operational hardening measures. Organizations should immediately upgrade to MongoDB versions 4.0.11, 3.6.14, or 3.4.22 where the vulnerability has been addressed through proper validation of PID file contents. Additionally, system administrators should review file permissions for PID files and ensure that only the MongoDB service account has write access to these critical files. The init script should be modified to validate PIDs against the current process list and ensure that only legitimate MongoDB processes are targeted for termination. Implementing proper file system permissions and monitoring for unauthorized modifications to PID files can help detect potential exploitation attempts. Security teams should also consider implementing process monitoring to detect unusual kill operations and establish baseline behavior for MongoDB service management operations. The vulnerability demonstrates the critical importance of proper input validation in system-level scripts and highlights the need for privilege separation in service management operations, particularly when dealing with process termination commands that can affect system stability and security posture.