Security Bulletin: IBM HTTP Server is vulnerable to HTTP request splitting due to the included Apache HTTP Server (CVE-2023-25690)

Summary

IBM HTTP Server used by IBM WebSphere Application Server is vulnerable to HTTP request splitting when using mod_proxy or the Web Server Plug-in due to the included Apache HTTP Server. This has been addressed in the remediation section.

Vulnerability Details

CVEID:CVE-2023-25690
**DESCRIPTION:**Apache HTTP Server is vulnerable to HTTP request splitting attacks, caused by an error when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch. A remote attacker could exploit this vulnerability to bypass access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning.
CVSS Base score: 6.1
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/249287 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)

Affected Products and Versions

This vulnerability affects the following version and release of IBM HTTP Server (powered by Apache) component in all editions of IBM WebSphere Application Server and bundling products.

Remediation/Fixes

IBM strongly recommends addressing the vulnerability now by applying a currently available interim fix or fix pack that contains APAR PH53014.

For IBM HTTP Server used by IBM WebSphere Application Server:

For V9.0.0.0 through 9.0.5.15:
· Upgrade to minimal fix pack levels as required by interim fix and then apply Interim Fix PH53014
--OR–
· Apply Fix Pack 9.0.5.16 or later (targeted availability 2Q2023).

For V8.5.0.0 through 8.5.5.23:
· Upgrade to minimal fix pack levels as required by interim fix and then apply Interim Fix PH53014
--OR–
· Apply Fix Pack 8.5.5.24 or later (targeted availability 3Q2023).

Additional interim fixes may be available and linked off the interim fix download page.

Important Note

IBM strongly suggests that all System z customers be subscribed to the System z Security Portal to receive the latest critical System z security and
integrity service. If you are not subscribed, see the instructions on the System z Security web site. Security and integrity APARs and associated fixes will
be posted to this portal. IBM suggests reviewing the CVSS scores and applying all security or integrity fixes as soon as possible to minimize any potential
risk.

Workarounds and Mitigations

None