Kerberos is a Greek name for a ferocious three-headed dog that guards things in Greek mythology. It is an authentication protocol used in Computer Networks.
It has a client-server architecture and protects against illegal eavesdropping and replay attacks. Kerberos can work on various operating systems, such as Windows, MacOS, and Unix-like operating systems like RHEL.

How Does Kerberos Work?

Let us say machine A wants to access a service that resides on machine B. Below are the steps involved:

1. Machine A authenticates itself to the Authentication Server which forwards the username to the Key Distribution Center (KDC).
2. KDC issues a ticket-granting ticket (TGT) which is timestamped and encrypted using the Ticket Granting Service.
3. This TGT is sent to Machine A.
4. Machine A sends the TGT to TGS. Machine B’s service is registered on TGS with a Service Principal Name (SPN).
5. Machine A sends SPN and TGT to TGS.
6. After TGS verifies SPN and TGT, it issues permission to Machine A to access the service provided by Machine B, by providing issue tickets and session keys to Machine A.

Disadvantages of Kerberos

But there are a few disadvantages of using Kerberos. Some of them are listed below:

• Single Point of Failure
• No standardized implementation of the Kerberos protocol
• Strict time requirements
• Complicated implementation

Vulnerabilities of Kerberos

Kerberos is an authentication protocol, but does it have any vulnerability? Can it be compromised?
Yes, Kerberos has vulnerabilities and hackers can develop ways to get into the network by using those.
Some of the methods used by hackers to crack Kerberos include brute force methods to guess passwords, the use of malware that can bypass Kerberos, the use of golden tickets to access your files, folders as well as Domain Controllers, and so on.

Future of Kerberos

Is Kerberos here to stay or is it going to be outdated?
Kerberos is here to stay. It has strong encryption algorithms to protect the tickets. It is so widely used, and it will be present over the years in one form or another.
Currently, there are no competitors in the market that can compete with Kerberos. It dominates the Single-Sign-On methodology. However, there is a weak link of passwords in Kerberos that can be easily cracked, so Multi-Factor Authentication is becoming more popular to protect online individuals.

Commands Used in Kerberos

Below are some of the commands used when working with Kerberos:

• kinit: The client uses the kinit command to request a Kerberos ticket from the server.
• kdestroy: The client uses the kdestroy command to invalidate any existing tickets on the client.
• klist: This command is used to check the list of active Kerberos tickets on the client machine.