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What is Kerberos, the network security protocol

Protect networks and connected devices, something essential

First of all we want to remember the importance of always keeping our secure networks. It is essential to prevent the entry of intruders who can steal information, control our equipment and, ultimately, put its proper functioning at risk. But this also applies to any device that we have connected. We must always keep them updated, encrypted, protected with programs.

Nowadays it is very common to have a large amount of computers connected to the network in our homes. What is known as the Internet of Things offers a wide range of possibilities. Many devices that work connected to the network are part of our day to day both at the home user level as well as companies and organizations. This means that we must take certain precautions.

When connecting two computers together, an important factor is to authenticate. We must verify security, identity, and thus be able to communicate with each other with total reliability. That’s where the Kerberos protocol comes in, which we’re going to talk about.

Kerberos, the protocol for verifying the identity of networked devices

As we have mentioned, Kerberos is a protocol that is used to authenticate two devices that connect to each other. It does not mean that you are going to authorize them, but to authenticate them. Its function is to identify each user through encryption. This password is only known to the user of each device. It was designed by MIT, which is short for Massachusetts Institute of Technology.

Let’s say there are two computers connected in a network that may be insecure. Thanks to this protocol, these two devices will prove their identity to each other in a reliable way. Basically it could be used when connecting a client to a server.

One point to note in using Kerberos is that it uses symmetric key. This means that it is necessary to have a third party who can give confidence. Specifically, it is based on the Needham-Schroeder symmetric key protocol. They depend on a key distribution center, which has two independent parts, such as an authentication server and a ticket issuing server.

Keep in mind that it maintains a database with the secret keys. Each of the entities will have a secret key known only to it and to Kerberos. This serves to prove identity. To communicate, it generates a session key and in this way communications are encrypted.

Therefore, we can summarize that Kerberos is a computer network security protocol that authenticates service requests between two or more trusted hosts through an untrusted network, such as the Internet. It uses secret key encryption and a trusted third party to authenticate client-server applications to verify user identities.

Kerberos uses

We have explained what is kerberos. We have seen that it is a network security protocol used to authenticate requests between devices. It is important to avoid problems and to know that communications will be reliable between a client and a server. Now we are also going to talk about some uses that we can give to this protocol.

We can say that it is found in many digital devices. It is used especially in secure systems that depend on auditing and authentication functions. It is an alternative system to others such as SSH, POP and SMTP. It can be used for Posix and Active Directory, NFS, and Samba authentication.

In a typical example of using Kerberos, a client acts on behalf of the user and initiates a communication to request a certain service. On the other side is the server, which is the one that hosts the service that the user tries to access. The authentication server performs the authorization requested by the client.

When authentication is successful, the server generates a ticket. That ticket is sent to the client and assures the other servers that the client is authenticated.

The authentication server is separated into three parts. One of them is the database, another the authentication server and another the server to grant tickets. All of them are on the server known as Key distribution center.

Kerberos has been attacked over time

Keep in mind that today in the Informatic security there is nothing infallible. What may be safe today may not be safe tomorrow. We speak for example of the encryption of Wi-Fi networks. We have seen how over time there have been problems and hackers have been able to break them.

Something like this has happened with Kerberos. Although it is a very reliable network security protocol, the truth is that over time cybercriminals have found a way to bypass it, forge tickets or guess passwords.

However, Kerberos is still a very important and widely used security protocol. Uses very strong encryption algorithm and that can hardly be exploited, although vulnerabilities and problems could occur.

To ensure that everything works well, that using this protocol and others like it is secure, we must at all times use passwords that are secure. Hence, we must think about which key to use, never repeat it in other places, generate them totally random and with enough length to make brute force attacks as difficult as possible.

Ultimately, Kerberos is a very important network security protocol used today. It is not something new, since it has been with us for many years, but it is still one of the most reliable to authenticate devices.

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