Impact

All users of pysaml2 that use the default CryptoBackendXmlSec1 backend and need to verify signed SAML documents are impacted. pysaml2 <= 6.4.1 does not ensure that a signed SAML document is correctly signed. The default CryptoBackendXmlSec1 backend is using the xmlsec1 binary to verify the signature of signed SAML documents, but by default, xmlsec1 accepts any type of key found within the given document. xmlsec1 needs to be configured explicitly to only use only x509 certificates for the verification process of the SAML document signature.

Patches

Users should upgrade to pysaml2 v6.5.0.

Workarounds

No workaround provided at this point.

References

This issue has been reported in the past at the xmlsec1 mailing list:
https://www.aleksey.com/pipermail/xmlsec/2013/009717.html

Credits

• Brian Wolff

For more information

If you have any questions or comments about this advisory:

• Open an issue in pysaml2
• Email us at the incident-response address