It is the year 2019. Humanity has almost won its long-standing war against Single-Sign On (SSO) bugs. The last of them were discovered and eradicated some time ago and the world is now living in an era of prosperity while the Auth Federation enjoys peaceful CVE-free times. However, while things seem to be running smoothly, new bugs are brewing at the core of major implementation libraries. This is probably the last chance for the evil empire to launch a world scale attack against the Auth Federation. In this talk, we will present two new techniques: 1) A new breed of SAML implementation flaws that break XML signature validation and enable arbitrary modification of the SAML assertion, which enables attackers to authenticate as arbitrary users or grant themselves arbitrary authorization claims. Although any implementation may be affected by this flaw, we will show how it affects Microsoft Windows Identity Framework (WIF) applications, Windows Communication Foundation (WCF) web services, and flagship products such as SharePoint and Exchange Servers. 2) A bug in the .NET crypto library, which may allow attackers to gain Remote Code Execution (RCE) or Denial of Service (DoS) depending on the availability of code gadgets in the target server. A new tool to detect this type of vulnerability will also be discussed and released. Alvaro Muñoz Alvaro Muñoz (@pwntester) is Principal Security Researcher at Micro Focus Fortify where he researches new software vulnerabilities and implement systems to detect them. His research focuses on web application frameworks where he looks for vulnerabilities or unsafe uses of APIs. Before joining the research team, he worked as an Application Security Consultant helping enterprises to deploy application security programs. Muñoz has presented at many Security conferences including BlackHat, DEF CON, RSA, OWASP AppSec US & EU, JavaOne, etc and holds several infosec certifications, including OSCP, GWAPT and CISSP. He plays CTFs with Spanish int3pids team. Oleksandr Mirosh Oleksandr Mirosh has over 11 years of computer security experience, including vulnerability research, penetration testing, reverse engineering, fuzzing, developing exploits and consulting. He is working for Fortify Software Security Research team in Micro Focus investigating and analyzing new threats, vulnerabilities, security weaknesses, new techniques of exploiting security issues and development vulnerability detection, protection and remediation rules. In the past, he has performed a wide variety of security assessments, including design and code reviews, threat modelling, testing and fuzzing in order to identify and remove any existing or potentially emerging security defects in the software of various customers