  SAML assertions are becoming popular method for passing authentication and
authorisation information between identity providers and consumers using
various single sign-on protocols. However their practical security strongly
depends on correct implementation, especially on the consumer side. Somorovsky
and others have demonstrated a number of XML signature related vulnerabilities
in SAML assertion validation frameworks. This article demonstrates how bad
library documentation and examples can lead to vulnerable consumer code and how
this can be avoided.
