Advisories for Composer/Simplesamlphp/Saml2-Legacy package

SimpleSAMLphp's HTTP-Artifact receive path can treat an unsigned embedded SAML Response as cryptographically valid for the wrong IdP. In the HTTPArtifact::receive() flow, the SOAP ArtifactResponse receives a TLS-based validator from SOAPClient::addSSLValidator(). The embedded SAML Response then receives a validator that delegates signature validation to that outer ArtifactResponse. Later, the SP validates the embedded Response against metadata selected from the embedded response issuer, not necessarily the artifact issuer. The critical issue …

This library turned out to be vulnerable to Denial-of-Service attacks using XPath transforms. A mitigation has been put in place to restrict the number of transforms and to restrict transforms to only the transform-algorithms mentioned in the SAML 2.0 Core Specifications (and specifically refuse XPath transforms).

There's a signature confusion attack in the HTTPRedirect binding. An attacker with any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned message. I believe that it exists for v4 only. I have not yet developed a PoC. V5 is well designed and instead builds the signed query from the same message that will be consumed.

When loading an (untrusted) XML document, for example the SAMLResponse, it's possible to induce an XXE.

Summary When loading an (untrusted) XML document, for example the SAMLResponse, it's possible to induce an XXE.