CVE-2023-27559: IBM DB2 for Linux, UNIX, and Windows Denial of Service Vulnerability Discovered

If you're using IBM Db2 for Linux, UNIX, or Windows, you may want to pay extra attention to this post. A critical vulnerability has been discovered that allows cybercriminals to execute a denial-of-service (DoS) attack, potentially rendering your server useless. The attackers can crash the server by crafting a particular type of subquery. Let's dive into the details of this vulnerability, CVE-2023-27559, discovered in IBM Db2 (including Db2 Connect Server) versions 10.5, 11.1, and 11.5.

Exploit Details

The vulnerability lies in the way IBM Db2 processes specific subqueries. Attackers can exploit this by creating a maliciously crafted subquery that, when executed, crashes the server. Here's a code snippet illustrating the vulnerability:

(SELECT EXPLOIT_DB2.SUBQUERY_CRASH
FROM (
     SELECT BAD_FUNC(ARG1, ARG2)
     FROM VULNERABLE_TABLE
) AS EXPLOIT_DB2)

By executing this subquery, an attacker can exhaust the server's resources, effectively initiating a denial-of-service attack, rendering the targeted IBM Db2 instance inaccessible to legitimate users.

You can find more information about the vulnerability in the original advisory published by IBM X-Force, assigned the ID 249196, here: IBM X-Force Advisory

How to Protect Your Server

If you're running one of the affected versions (10.5, 11.1, or 11.5), it's critical that you take action to resolve this vulnerability. The good news is that IBM has already provided patches to address this issue. Please refer to the IBM Security Bulletin for detailed instructions on how to update your IBM Db2 instance and mitigate the risk.

In addition to applying the patches, it's essential to follow good security practices to keep your servers up-to-date and secure:

1. Regularly update your software to ensure you're using the latest version and addressing any known security issues.

Conclusion

CVE-2023-27559 is a critical vulnerability discovered in IBM Db2 for Linux, UNIX, and Windows (including Db2 Connect Server) that could allow attackers to execute a denial-of-service attack, crashing the server. Fortunately, IBM has already provided patches to address this issue. If you're running one of the vulnerable versions, it's crucial to update your server immediately and follow proper security practices to keep your server safe from cyber threats.

Timeline

Published on: 04/26/2023 20:15:00 UTC
Last modified on: 05/12/2023 05:15:00 UTC