CVE-2023-25930: IBM Db2 Denial of Service Vulnerability

CVE-2023-25930 Overview

IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) versions 10.1, 11.1, and 11.5 contains a denial of service vulnerability. Under rare conditions, setting a special register may cause the Db2 server to terminate abnormally, resulting in service disruption. This vulnerability is tracked under IBM X-Force ID: 247862.

Critical Impact

Successful exploitation can cause the Db2 database server to crash unexpectedly, leading to service unavailability and potential data access disruption for dependent applications and services.

Affected Products

• IBM Db2 10.5 (including Fix Packs 1-10)
• IBM Db2 11.1.4 (including Fix Packs 1-6)
• IBM Db2 11.5 for Linux, UNIX, and Windows

Discovery Timeline

• April 28, 2023 - CVE-2023-25930 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-25930

Vulnerability Analysis

This vulnerability stems from improper input validation (CWE-20) in IBM Db2's handling of special register operations. The Db2 database engine fails to properly validate or sanitize certain values when special registers are configured, leading to an uncontrolled state that causes the server process to terminate abnormally.

The vulnerability requires network access to exploit but has high attack complexity due to the specific conditions required for successful exploitation. No authentication is required, and no user interaction is needed. While the vulnerability does not impact confidentiality or integrity, it poses a significant availability risk to organizations relying on Db2 for critical database operations.

Root Cause

The root cause is improper input validation (CWE-20) within the Db2 special register handling mechanism. When certain edge-case values are assigned to special registers, the database engine enters an invalid state that triggers an unhandled exception, causing the server process to crash. This represents a failure to properly validate boundary conditions and exceptional inputs during register configuration operations.

Attack Vector

The attack vector is network-based, allowing remote attackers to trigger the vulnerability without authentication. The exploitation requires sending specially crafted database commands that manipulate special register settings in a way that triggers the vulnerable code path.

The vulnerability manifests when specific register values are set under particular conditions. Due to the high attack complexity requirement, successful exploitation depends on timing and system state factors. Attackers with network access to the Db2 server can potentially cause repeated denial of service conditions by targeting this flaw.

For technical details on the specific exploitation mechanism, refer to the IBM Support Document #6985677 and the IBM X-Force Vulnerability #247862.

Detection Methods for CVE-2023-25930

Indicators of Compromise

• Unexpected Db2 server process terminations without corresponding system errors
• Database connection failures correlating with specific SQL command executions
• Db2 diagnostic logs showing abnormal termination events related to register operations
• Repeated service restarts for Db2 instances within short time periods

Detection Strategies

• Monitor Db2 diagnostic logs (db2diag.log) for abnormal termination patterns and crash signatures
• Implement database activity monitoring to detect unusual special register manipulation commands
• Configure alerting for unexpected Db2 process restarts or service availability changes
• Use SentinelOne Singularity to monitor process behavior and detect abnormal database server terminations

Monitoring Recommendations

• Enable comprehensive Db2 audit logging to capture all administrative and configuration commands
• Set up real-time alerts for Db2 service availability using endpoint monitoring solutions
• Monitor network traffic patterns to Db2 ports for anomalous command sequences
• Implement baseline monitoring for Db2 process uptime and restart frequency

How to Mitigate CVE-2023-25930

Immediate Actions Required

• Apply the latest security patches from IBM for affected Db2 versions immediately
• Review and restrict network access to Db2 database servers to trusted sources only
• Implement network segmentation to limit exposure of database infrastructure
• Enable enhanced logging on Db2 instances to aid in detection of exploitation attempts

Patch Information

IBM has released security updates to address this vulnerability. Organizations should apply the appropriate fix packs for their Db2 version. Detailed patch information is available in the IBM Support Document #6985677. Additional information can be found in the NetApp Security Advisory NTAP-20230511-0010 for NetApp customers using affected IBM Db2 versions.

Workarounds

• Restrict network access to Db2 servers using firewall rules to limit exposure to trusted hosts only
• Implement database activity monitoring to detect and block suspicious register manipulation attempts
• Consider deploying database proxy solutions to filter potentially malicious commands
• If immediate patching is not possible, limit database administrative privileges to essential personnel

# Example: Restrict Db2 connections to trusted IP ranges using iptables
iptables -A INPUT -p tcp --dport 50000 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 50000 -j DROP

# Example: Enable Db2 audit logging for enhanced monitoring
db2audit configure scope all status both
db2audit start