CVE-2020-4945 in DB2
Summary
by MITRE • 06/25/2021
IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 11.5 could allow an authenticated user to overwrite arbirary files due to improper group permissions. IBM X-Force ID: 191945.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/26/2021
IBM Db2 version 11.5 presents a critical security vulnerability that enables authenticated users to overwrite arbitrary files through improper group permissions within the database system. This vulnerability specifically affects the Db2 Connect Server component and impacts installations across Linux, UNIX, and Windows operating systems. The flaw stems from inadequate permission controls that allow users with legitimate access to manipulate file system objects beyond their intended scope, creating a significant vector for privilege escalation and data integrity compromise.
The technical implementation of this vulnerability involves the database server's handling of group permissions during file operations and system interactions. When authenticated users establish connections to the Db2 server, they can exploit the misconfigured group access controls to target files outside their designated access boundaries. This misconfiguration allows attackers to manipulate critical system files, configuration data, or user information stored within the database environment, potentially leading to complete system compromise. The vulnerability operates at the file system level rather than through traditional database query mechanisms, making it particularly dangerous as it bypasses standard database security controls.
The operational impact of this vulnerability extends beyond simple file overwrites to encompass potential system-wide compromise and data corruption. An authenticated attacker could leverage this flaw to modify critical database configuration files, overwrite system binaries, or manipulate backup and log files that could be used for further exploitation or to cover tracks. The vulnerability particularly affects organizations that rely on Db2 for mission-critical applications, as it could lead to unauthorized data modification, service disruption, or complete system takeover. The ability to overwrite arbitrary files undermines the fundamental security assumptions of the database environment and could enable attackers to establish persistent access or escalate privileges to system administrator levels.
Organizations should implement immediate mitigations including applying the vendor-provided security patches and updates, reviewing and tightening group permissions on Db2 installation directories, and implementing monitoring for unauthorized file modifications. Security teams should also conduct comprehensive audits of file system permissions across all Db2 installations and establish network segmentation to limit access to database servers. The vulnerability aligns with CWE-276 which describes inadequate permissions for file system objects, and represents a significant concern from an ATT&CK perspective under privilege escalation and defense evasion techniques. Organizations must also consider implementing additional controls such as file integrity monitoring, privileged access management, and regular security assessments to detect and prevent exploitation attempts. Proper access control enforcement and regular security updates remain critical to maintaining database integrity and preventing unauthorized file manipulation across all system components.