Security Bulletin: Apache CXF (Publicly disclosed vulnerability)

Summary

CXF supports (via JwtRequestCodeFilter) passing OAuth 2 parameters via a JWT token as opposed to query parameters (see: The OAuth 2.0 Authorization Framework: JWT Secured Authorization Request (JAR)). Instead of sending a JWT token as a “request” parameter, the spec also supports specifying a URI from which to retrieve a JWT token from via the “request_uri” parameter. CXF was not validating the “request_uri” parameter (apart from ensuring it uses "https) and was making a REST request to the parameter in the request to retrieve a token. This means that CXF was vulnerable to DDos attacks on the authorization server, as specified in section 10.4.1 of the spec. This issue affects Apache CXF versions prior to 3.4.3; Apache CXF versions prior to 3.3.10.

Vulnerability Details

CVEID:CVE-2021-22696
**DESCRIPTION:**Apache CXF is vulnerable to a denial of service, caused by improper validation of request_uri parameter by the OAuth 2 authorization service. By sending a specially-crafted request, a remote attacker could exploit this vulnerability to cause a denial of service condition on the authorization server.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/199335 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

ITNM 4.2 Fix Pack 13 can be downloaded from Fix Central

Workarounds and Mitigations

None