This is part 1 in a new series about secure control of egress traffic in Istio that I am going to publish. In this installment, I explain why you should apply egress traffic control to your cluster, the attacks involving egress traffic you want to prevent, and the requirements for your system to do so. Once you agree that you should control the egress traffic coming from your cluster, the following questions arise: What requirements does a system have for secure control of egress traffic?
Which is the best solution to fulfill these requirements? (spoiler: Istio in my opinion) Future installments will describe the implementation of the secure control of egress traffic in Istio and compare it with other solutions.
The most important security aspect for a service mesh is probably ingress traffic. You definitely must prevent attackers from penetrating the cluster though ingress APIs. Having said that, securing the traffic leaving the mesh is also very important.
Once your cluster is compromised, and you must be prepared for that scenario, you want to reduce the damage as much as possible and prevent the attackers from using the cluster for further attacks on external services and legacy systems outside of the cluster. To achieve that goal, you need secure control of egress traffic.
Source: istio.io