Montag, 24. Juni 2019

Probing for XML Encryption Weaknesses in SAML with EsPReSSO

Security Assertion Markup Language (SAML) is an XML-based standard commonly used in Web Single Sign-On (SSO) [1]. In SAML, the confidentiality of transferred authentication statements against intermediaries can be provided using XML Encryption [2]. However, implementing XML Encryption in a secure way can be tricky and several attacks on XML Encryption have been identified in the past [3] [4]. Therefore, when auditing a SAML endpoint, one should always consider testing for vulnerabilities in the XML Encryption implementation.

This blog post introduces our latest addition to the SAML Attacker of our BurpSuite extension EsPReSSO: the Encryption Attack tab. The new tab allows for easy manipulation of the encrypted parts within intercepted SAML responses and can, therefore, be used to quickly assess whether the SAML endpoint is vulnerable against certain XML Encryption attacks.

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