CVE-2018-1977 in DB2
Summary
by MITRE
IBM DB2 for Linux, UNIX and Windows 11.1 (includes DB2 Connect Server) contains a denial of service vulnerability. A remote, authenticated DB2 user could exploit this vulnerability by issuing a specially-crafted SELECT statement with TRUNCATE function. IBM X-Force ID: 154032.
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Analysis
by VulDB Data Team • 06/19/2023
The vulnerability identified as CVE-2018-1977 affects IBM DB2 for Linux, UNIX and Windows version 11.1 including the DB2 Connect Server component. This represents a significant denial of service weakness that can be exploited by remote authenticated users. The flaw specifically manifests when a malicious user executes a carefully constructed SELECT statement that incorporates the TRUNCATE function, which triggers an unexpected system behavior leading to service disruption. The vulnerability exists within the database engine's handling of specific SQL operations and demonstrates a critical design oversight in the input validation and error handling mechanisms. Organizations utilizing this database version face potential operational risks including system unavailability and service degradation that could impact business continuity and data accessibility.
The technical exploitation of this vulnerability occurs through the manipulation of SQL query execution pathways within the DB2 database system. When a user with valid authentication credentials submits a SELECT statement containing the TRUNCATE function, the database engine fails to properly validate or handle this anomalous operation sequence. This improper handling causes the system to enter an unstable state where normal database operations become unavailable or the entire database service becomes unresponsive. The vulnerability stems from insufficient input sanitization and inadequate boundary checking within the SQL parser and execution engine components. According to CWE classification, this vulnerability maps to CWE-129 Input Validation and Representation, specifically involving improper handling of malformed input sequences that should be rejected during parsing. The flaw demonstrates characteristics of CWE-400 Uncontrolled Resource Consumption, where the malformed query consumption of system resources leads to service disruption rather than direct system compromise.
The operational impact of this vulnerability extends beyond simple service interruption to encompass broader security and business implications. Remote authenticated attackers can leverage this weakness to cause sustained denial of service conditions that may require manual intervention to restore normal operations. Database administrators face the challenge of identifying and mitigating attacks that occur through legitimate user accounts, making detection more difficult compared to external attacks. The vulnerability affects critical database infrastructure components including DB2 Connect Server which serves as a gateway for remote database access, potentially amplifying the impact across multiple connected systems. From an ATT&CK framework perspective, this vulnerability aligns with T1499.004 Network Denial of Service and T1078 Valid Accounts, as it requires legitimate authentication credentials to exploit but results in service disruption rather than data exfiltration. Organizations may experience cascading effects including application downtime, user access restrictions, and potential revenue loss during service restoration periods.
Mitigation strategies for CVE-2018-1977 should focus on immediate patch application from IBM as the primary remediation measure. Organizations must ensure all DB2 instances running version 11.1 receive the appropriate security updates and hotfixes released by IBM to address the specific TRUNCATE function handling issue. Network segmentation and access controls should be implemented to limit authentication scope and reduce attack surface exposure. Database administrators should monitor for unusual query patterns and implement logging controls to detect potential exploitation attempts. Input validation mechanisms should be enhanced to prevent malformed SQL statements from reaching the database engine, particularly those involving function combinations that could trigger the vulnerability. Regular security assessments and penetration testing should include validation of SQL injection and resource consumption attack vectors. Additionally, implementing database activity monitoring solutions can help detect anomalous behavior patterns that may indicate exploitation attempts. Organizations should also consider implementing database firewalls or query filtering mechanisms that can block or quarantine suspicious SQL operations before they reach the core database engine. The remediation process should include thorough testing of patches in non-production environments to ensure compatibility with existing database configurations and applications before deployment to production systems.