Security Bulletin: IBM WebSphere Application Server Liberty is vulnerable to a denial of service (CVE-2023-44487)

Summary

IBM WebSphere Application Server Liberty is vulnerable to a denial of service with the servlet-3.1, servlet-4.0, servlet-5.0, or servlet-6.0 feature with the HTTP/2 protocol enabled.

Vulnerability Details

CVEID:CVE-2023-44487
**DESCRIPTION:**Multiple vendors are vulnerable to a denial of service, caused by a Rapid Reset flaw in the HTTP/2 protocol. By sending numerous HTTP/2 requests and RST_STREAM frames over multiple streams, a remote attacker could consume excessive server side resources.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/268044 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Affected Products and Versions

Remediation/Fixes

IBM strongly recommends addressing the vulnerability now by applying a currently available interim fix or fix pack that contains the APAR PH57878. To determine if a feature is enabled for IBM WebSphere Application Server Liberty, refer to How to determine if Liberty is using a specific feature. To determine if the HTTP/2 protocol is enabled with Liberty Servlet features see HTTP/2 Support for Liberty.

For IBM WebSphere Application Server Liberty 18.0.0.2 - 23.0.0.11 using the servlet-3.1, servlet-4.0, servlet-5.0, or servlet-6.0 feature(s) with the HTTP/2 protocol enabled:
· Upgrade to minimal fix pack levels as required by interim fix and then apply Interim Fix PH57878
--OR–
· Apply Liberty Fix Pack 23.0.0.12 or later (targeted availability 4Q2023).

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

Workarounds and Mitigations

None