Certificates – Why and What for
In this article I would like to give you an insight into the topic “Securing the Internet-based exchange of information through certificates”. I’ll take a quick look back at the beginnings of the Internet and the use of protocols such as HTTP, SMTP, POP … and their encrypted transport via SSL or TLS. Above all, however, I would like to explain to you how you can use public certificates with Univention Corporate Server to secure your data transfer or also how you can create trustworthy certificates by yourself with Let’s Encrypt. Completely secure and free of charge on top.
The two authentication standards SAML (Security Assertion Markup Language) and OpenID Connect have already been available to UCS users for some time. So far, however, these two technologies have been two separated worlds. If some of the web services used SAML and others OpenID Connect for the authentication against UCS’ identity management, users were forced to log in twice in those environments with multiple services. With the support of the Kopano team, we were able to release an extension of the app “OpenID Connect ID” in the App Center. This is integrating the two standards with each other and thus allows a single authentication process by the end user.
I would like to briefly explain how a single sign-on generally works with UCS. Then I explain the interaction of Kerberos, SAML, and OpenID Connect and show you which functions the new implementation of Kopano Konnect offers to UCS users.
Version 4.4-4 of Univention Corporate Server (UCS) comes with some cool new features, one of them being the new AD Connector app. It makes the synchronization of password hashes between a Microsoft Active Directory domain and a UCS domain significantly more secure and less error-prone. While previous versions could only synchronize NTLM hashes, the AD Connector of UCS 4.4-4 also reads newer hashes, the so-called Kerberos keys which allow single sign-on (SSO) to different applications.
I am a second-year trainee at Univention (job description: IT specialist for application development). I was involved in the development of the new feature and mainly had to deal with three tasks: the AD Connector itself, the OpenLDAP overlay module, and the S4 Connector (Samba). In this blog post I’m going to explain what Kerberos hashes are and how I implemented the new feature.
By default, UCS users can enter the password incorrectly any number of times without being locked out by the system. In order to make brute force attacks to crack passwords more difficult, admins can set up an automatic lockout that prevents an account from being accessed after a user-defined number of failed attempts.
Univention Corporate Server offers several methods for authentication and authorization. In this blog article I will show you how to log failed login attempts to the system via PAM stack, OpenLDAP and Samba respectively and how you as an admin can set a limit for the number of unsuccessful logins.