CVE-2023-27558: Privilege Escalation Vulnerability in IBM Db2 on Windows 10.5, 11.1, and 11.5 Exploiting Unquoted Service Path

In this post, we will discuss CVE-2023-27558, a vulnerability in IBM Db2 that could lead to privilege escalation on Windows versions 10.5, 11.1, and 11.5. The vulnerability is caused by at least one installed service utilizing an unquoted service path, which allows a local attacker to gain elevated privileges by inserting an executable file in the service path. IBM X-Force has assigned this vulnerability an ID of 249194.

We will cover detailed information on the vulnerability, provide code snippets that demonstrate how the exploit can be executed, and share links to original references and resources that can help address this issue.

Vulnerability Details:

IBM Db2 for Windows 10.5, 11.1, and 11.5 could be vulnerable to a privilege escalation attack. This attack is made possible because of the unquoted service path used in at least one of the installed services. When a service path is unquoted, it allows attackers to potentially exploit spaces within the path and insert an executable that would be run in place of the intended service executable.

In this case, a local attacker could exploit the vulnerability by inserting an executable file with a malicious payload into the path of the affected service, effectively granting them elevated privileges on the system.

Exploit Example

Let's take a look at a code snippet representing how this exploit could work. Assume that the affected service has an unquoted path like this:

C:\Program Files\IBM\Db2\Example\Service.exe

In this scenario, the attacker can insert a malicious executable named "Program.exe" in the "C:\" directory. The service will then run this malicious executable instead of the intended Service.exe:

C:\
 |--> Program.exe (malicious executable inserted by the attacker)
 |--> Program Files
      |--IBM
         |--Db2
            |--Example
               |--Service.exe (intended service executable)

When the affected service is started, the malicious executable "Program.exe" will be run with the service's elevated privileges, which would allow the attacker to execute their payload with these elevated privileges.

Mitigation and Recommendations

IBM has released patches to address CVE-2023-27558 for the affected Db2 versions on Windows. To secure your systems, apply the appropriate patch as follows:

For Db2 version 11.5, apply Mod Pack 3.

You can find detailed instructions and download links for the patches from IBM's official support page here: IBM Db2 Security Vulnerabilities and Fixes

Additionally, as a best practice, always use quoted paths when working with Windows services. This mitigates the risk of attackers exploiting unquoted service paths to insert malicious executables.

Conclusion

CVE-2023-27558 is a privilege escalation vulnerability in IBM Db2 on Windows 10.5, 11.1, and 11.5 caused by unquoted service paths. An attacker can exploit the vulnerability to gain elevated system privileges by inserting a malicious executable into the service path. Applying the appropriate patches provided by IBM and following best practices, such as using quoted paths, can help secure your systems against this vulnerability.

References and Resources

1. CVE-2023-27558 - NVD - National Vulnerability Database
2. IBM Security Bulletin: Db2 for Windows...
3. IBM Db2 Security Vulnerabilities and Fixes
4. 249194 - Analysis | X-Force Exchange

Timeline

Published on: 07/10/2023 16:15:00 UTC
Last modified on: 08/18/2023 14:15:00 UTC