CVE-2018-1834 in DB2
Summary
by MITRE
IBM DB2 for Linux, UNIX and Windows (includes DB2 Connect Server) 9.7, 10.1, 10.5, and 11.1 contains a vulnerability that could allow a local user to escalate their privileges to root through a symbolic link attack. IBM X-Force ID: 150511.
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Analysis
by VulDB Data Team • 06/05/2023
This vulnerability exists within IBM DB2 database management system versions 9.7, 10.1, 10.5, and 11.1 running on Linux, UNIX, and Windows platforms including the DB2 Connect Server component. The flaw represents a privilege escalation vulnerability that allows local attackers to elevate their system privileges to root level through a carefully crafted symbolic link attack. The vulnerability stems from insufficient validation of symbolic links during file operations within the database system's administrative functions. Attackers can exploit this weakness by creating malicious symbolic links that point to critical system files or directories, then triggering the vulnerable DB2 processes to follow these links, thereby gaining unauthorized root access to the underlying operating system.
The technical implementation of this vulnerability aligns with CWE-59, which describes improper link resolution without limit checks, and CWE-269, which addresses privileges issues in database management systems. The attack vector specifically targets the database administrator's privilege escalation capabilities within the DB2 environment. When DB2 processes execute certain administrative commands or file operations, they fail to properly validate or sanitize symbolic link references, allowing attackers to manipulate the file system traversal behavior. This vulnerability operates under the premise that database processes run with elevated privileges, making the symbolic link attack particularly dangerous as it can be leveraged to gain complete system control. The flaw is classified as a local privilege escalation issue because it requires physical access to the system or a pre-existing low-privilege account to exploit effectively.
The operational impact of this vulnerability extends beyond simple privilege escalation as it represents a critical security weakness that could lead to complete system compromise. Once an attacker gains root access through this vulnerability, they can modify system files, install persistent backdoors, access all database contents, and potentially use the compromised system as a pivot point for attacking other networked systems. The vulnerability affects all IBM DB2 versions mentioned, indicating a widespread issue that would impact numerous enterprise database deployments. Organizations running these database versions face significant risk of unauthorized access to sensitive data and system resources, potentially leading to data breaches, system downtime, and regulatory compliance violations.
Mitigation strategies for this vulnerability should include immediate application of IBM's security patches and updates, which address the symbolic link validation issues in the affected DB2 versions. System administrators should also implement principle of least privilege controls, ensuring that DB2 processes run with minimal required privileges rather than root access. Additional protective measures include monitoring for unauthorized symbolic link creation in database directories, implementing file integrity monitoring solutions, and conducting regular security assessments of database system configurations. Organizations should also consider implementing network segmentation to limit access to database servers and establish robust logging and alerting mechanisms to detect potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation and privilege management in database systems, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploits and T1548 which addresses abuse of privileges for persistence and escalation.