CVE-2023-26022 Overview
CVE-2023-26022 is a denial of service vulnerability affecting IBM Db2 for Linux, UNIX and Windows, including Db2 Connect Server. The vulnerability allows attackers to crash the database server by triggering an Out of Memory (OOM) condition through the DBMS_OUTPUT module. This can result in significant service disruption for organizations relying on IBM Db2 for critical database operations.
Critical Impact
Remote attackers can cause complete database service unavailability without authentication, potentially disrupting business-critical applications and data access.
Affected Products
- IBM Db2 10.5 (all fix packs through FP10)
- IBM Db2 11.1.4 (all fix packs through FP6)
- IBM Db2 Connect Server (corresponding versions)
Discovery Timeline
- April 28, 2023 - CVE-2023-26022 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2023-26022
Vulnerability Analysis
This denial of service vulnerability resides in the DBMS_OUTPUT module of IBM Db2, which is commonly used for debugging and outputting information from stored procedures and PL/SQL blocks. The vulnerability is triggered when the module fails to properly handle memory allocation during output operations, leading to an uncontrolled Out of Memory condition that crashes the entire database server.
The vulnerability is classified under CWE-20 (Improper Input Validation), indicating that the underlying issue stems from insufficient validation of input that can lead to excessive memory consumption. An attacker can exploit this remotely over the network without requiring authentication or user interaction, making it particularly dangerous for internet-exposed database instances.
Root Cause
The root cause of CVE-2023-26022 lies in improper input validation within the DBMS_OUTPUT module. The module fails to implement adequate bounds checking or resource limits when processing output buffer operations. This allows specially crafted requests to allocate excessive amounts of memory, eventually exhausting available system resources and causing the Db2 server process to crash.
The DBMS_OUTPUT module, which provides a simple way to display output and debugging information from PL/SQL subprograms, does not properly validate the size or frequency of buffer allocations requested by users. This oversight enables attackers to force the server into an OOM state.
Attack Vector
The attack can be executed remotely over the network. An attacker with network access to the Db2 server can send malicious requests that abuse the DBMS_OUTPUT module's buffer allocation functionality. Since no authentication is required, any network-accessible Db2 instance running a vulnerable version is at risk.
The exploitation scenario involves:
- Establishing a connection to the target Db2 server
- Executing operations that leverage the DBMS_OUTPUT module
- Manipulating buffer allocation requests to consume excessive memory
- Causing the server to crash when memory is exhausted
The vulnerability affects both availability and operational continuity, as the database server crash requires manual intervention for recovery.
Detection Methods for CVE-2023-26022
Indicators of Compromise
- Unusual memory consumption spikes in Db2 server processes
- Frequent server crashes or unexpected restarts of the Db2 service
- Error logs indicating Out of Memory conditions in DBMS_OUTPUT operations
- Abnormal patterns of DBMS_OUTPUT module usage in database activity logs
Detection Strategies
- Monitor Db2 diagnostic logs for OOM-related errors and DBMS_OUTPUT module failures
- Implement memory threshold alerts on database servers to detect abnormal consumption patterns
- Review database connection logs for suspicious activity patterns targeting stored procedures
- Deploy network monitoring to identify unusual traffic patterns to Db2 ports
Monitoring Recommendations
- Configure system-level memory monitoring with alerts at 80% utilization threshold
- Enable detailed logging for DBMS_OUTPUT module operations in Db2 diagnostic settings
- Implement automated health checks for Db2 service availability
- Establish baseline metrics for normal DBMS_OUTPUT usage to identify anomalies
How to Mitigate CVE-2023-26022
Immediate Actions Required
- Apply the latest IBM Db2 security patches from IBM Support Document #6985669
- Restrict network access to Db2 servers using firewall rules to limit exposure
- Review and restrict permissions for DBMS_OUTPUT module usage where possible
- Implement resource quotas and memory limits for database sessions
Patch Information
IBM has released security updates to address this vulnerability. Administrators should consult the IBM Support Document #6985669 for detailed patch information and download links. Additional technical details are available in the IBM X-Force Vulnerability #247868. NetApp customers should also review the NetApp Security Advisory NTAP-20230511-0010 for related guidance.
Workarounds
- Implement network segmentation to restrict access to Db2 servers from untrusted networks
- Configure resource governor or workload management to limit memory consumption per session
- Disable or restrict access to the DBMS_OUTPUT module if not required for operations
- Deploy application-level rate limiting for database connections
# Configuration example - Restrict network access to Db2 port
# Add firewall rules to limit access to trusted IP ranges
iptables -A INPUT -p tcp --dport 50000 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 50000 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
