Abstract. Single Sign-On (SSO) systems simplify login procedures by
using an an Identity Provider (IdP) to issue authentication tokens which
can be consumed by Service Providers (SPs). Traditionally, IdPs are
modeled as trusted third parties. This is reasonable for SSO systems like
Kerberos, MS Passport and SAML, where each SP explicitely specifies
which IdP he trusts. However, in open systems like OpenID and OpenID
Connect, each user may set up his own IdP, and a discovery phase is
added to the protocol flow. Thus it is easy for an attacker to set up its
own IdP
.
In this paper we use a novel approach for analyzing SSO authentication
schemes by introducing a malicious IdP. With this approach we evaluate
one of the most popular and widely deployed SSO protocols – OpenID
.
We found four novel attack classes on OpenID, which were not covered
by previous research, and show their applicability to real-life implementations.
As a result, we were able to compromise 11 out of 16 existing
OpenID implementations like Sourceforge, Drupal and ownCloud
.
We automated discovery of these attacks in a open source tool OpenID
Attacker, which additionally allows fine-granular testing of all parameters
in OpenID implementations.
Our research helps to better understand the message flow in the OpenID
protocol, trust assumptions in the different components of the system,
and implementation issues in OpenID components. It is applicable to
other SSO systems like OpenID Connect and SAML. All OpenID implementations
have been informed about their vulnerabilities and we
supported them in fixing the issues.
more here...........http://arxiv.org/pdf/1412.1623v1.pdf
using an an Identity Provider (IdP) to issue authentication tokens which
can be consumed by Service Providers (SPs). Traditionally, IdPs are
modeled as trusted third parties. This is reasonable for SSO systems like
Kerberos, MS Passport and SAML, where each SP explicitely specifies
which IdP he trusts. However, in open systems like OpenID and OpenID
Connect, each user may set up his own IdP, and a discovery phase is
added to the protocol flow. Thus it is easy for an attacker to set up its
own IdP
.
In this paper we use a novel approach for analyzing SSO authentication
schemes by introducing a malicious IdP. With this approach we evaluate
one of the most popular and widely deployed SSO protocols – OpenID
.
We found four novel attack classes on OpenID, which were not covered
by previous research, and show their applicability to real-life implementations.
As a result, we were able to compromise 11 out of 16 existing
OpenID implementations like Sourceforge, Drupal and ownCloud
.
We automated discovery of these attacks in a open source tool OpenID
Attacker, which additionally allows fine-granular testing of all parameters
in OpenID implementations.
Our research helps to better understand the message flow in the OpenID
protocol, trust assumptions in the different components of the system,
and implementation issues in OpenID components. It is applicable to
other SSO systems like OpenID Connect and SAML. All OpenID implementations
have been informed about their vulnerabilities and we
supported them in fixing the issues.
more here...........http://arxiv.org/pdf/1412.1623v1.pdf
