Monday, May 22, 2017

Security advisories issued for Apache CXF Fediz

Two security advisories were recently issued for Apache CXF Fediz. In addition to fixing these issues, the recent releases of Fediz impose tighter security constraints in some areas by default compared to older releases. In this post I will document the advisories and the other security-related changes in the recent Fediz releases.

1) Security Advisories

The first security advisory is CVE-2017-7661: "The Apache CXF Fediz Jetty and Spring plugins are vulnerable to CSRF attacks.". Essentially, both the Jetty 8/9 and Spring Security 2/3 plugins are subject to a CSRF-style vulnerability when the user doesn't complete the authentication process. In addition, the Jetty plugins are vulnerable even if the user does first complete the authentication process, but only the root context is available as part of this attack.

The second advisory is CVE-2017-7662: "The Apache CXF Fediz OIDC Client Registration Service is vulnerable to CSRF attacks". The OIDC client registration service is a simple web application that allows the creation of clients for OpenId Connect, as well as a number of other administrative tasks. It is vulnerable to CSRF attacks, where a malicious application could take advantage of an existing session to make changes to the OpenId Connect clients that are stored in the IdP.

2) Fediz IdP security constraints

This section only concerns the WS-Federation (and SAML-SSO) IdP in Fediz. The WS-Federation RP application sends its address via the 'wreply' parameter to the IdP. For SAML SSO, the address to reply to is taken from the consumer service URL of the SAML SSO Request. Previously, the Apache CXF Fediz IdP contained an optional 'passiveRequestorEndpointConstraint' configuration value in the 'ApplicationEntity', which allows the admin to specify a regular expression constraint on the 'wreply' URL.

From Fediz 1.4.0, 1.3.2 and 1.2.4, a new configuration option is available in the 'ApplicationEntity' called 'passiveRequestorEndpoint'. If specified, this is directly matched against the 'wreply' parameter. In a change that breaks backwards compatibility, but that is necessary for security reasons, one of 'passiveRequestorEndpointConstraint' or 'passiveRequestorEndpoint must be specified in the 'ApplicationEntity' configuration. This ensures that the user cannot be redirected to a malicious client. Similarly, new configuration options are available called 'logoutEndpoint' and 'logoutEndpointConstraint' which validate the 'wreply' parameter in the case of redirecting the user after logging out, one of which must be specified.

3) Fediz RP security constraints

This section only concerns the WS-Federation RP plugins available in Fediz. When the user tries to log out of the Fediz RP application, a 'wreply' parameter can be specified to give the address that the Fediz IdP can redirect to after logout is complete. The old functionality was that if 'wreply' was not specified, then the RP plugin instead used the value from the 'logoutRedirectTo' configuration parameter.

From Fediz 1.4.0, 1.3.2 and 1.2.4, a new configuration option is available called 'logoutRedirectToConstraint'. If a 'wreply' parameter is presented, then it must match the regular expression that is specified for 'logoutRedirectToConstraint', otherwise the 'wreply' value is ignored and it falls back to 'logoutRedirectTo'. 

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