CVE-2018-1780 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 could allow a local db2 instance owner to obtain root access by exploiting a symbolic link attack to read/write/corrupt a file that they originally did not have permission to access. IBM X-Force ID: 148803.
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Analysis
by VulDB Data Team • 06/05/2023
This vulnerability in IBM DB2 represents a critical privilege escalation flaw that exploits a symbolic link attack pattern commonly categorized under CWE-59. The vulnerability affects multiple versions of IBM DB2 including 9.7, 10.1, 10.5, and 11.1 across Linux, UNIX, and Windows platforms with DB2 Connect Server installations. The flaw specifically targets local db2 instance owners who can leverage improper file access controls to gain root privileges through manipulation of symbolic links. This represents a significant security risk as it allows users with limited db2 instance ownership permissions to escalate their privileges to the highest system level.
The technical implementation of this vulnerability stems from inadequate handling of symbolic links during file operations within the DB2 database management system. When db2 processes files that may contain symbolic links, the system fails to properly validate or resolve these links before performing read/write operations. This creates a race condition or path traversal scenario where an attacker can manipulate the symbolic link targets to access files that would normally be restricted. The vulnerability operates at the file system level and demonstrates poor input validation practices that align with ATT&CK technique T1068 for local privilege escalation through improper file permissions.
The operational impact of this vulnerability extends beyond simple privilege escalation as it fundamentally compromises the security model of the DB2 installation. Once an attacker gains root access through this method, they can manipulate database files, modify system configurations, install malicious software, or exfiltrate sensitive data without detection. The attack vector specifically targets the db2 instance owner context, making it particularly dangerous in multi-tenant environments where multiple users share the same system but have different security requirements. This vulnerability essentially undermines the principle of least privilege that is fundamental to secure system design.
Organizations should implement immediate mitigations including applying the relevant IBM security patches that address the symbolic link handling issues in DB2. System administrators should also implement additional controls such as restricting symbolic link creation permissions for db2 processes, monitoring file access patterns for suspicious symbolic link operations, and implementing proper file system permissions that prevent unauthorized access to critical system files. The vulnerability highlights the importance of proper privilege separation and demonstrates how seemingly minor file access control flaws can result in complete system compromise. Security monitoring should focus on detecting unauthorized file operations that may indicate exploitation attempts, particularly around db2 process execution and file system access patterns.