Cis K8s V1120 5.1.8

---
name: cis-k8s-v1120-5.1.8
description: "Limit use of the Bind, Impersonate and Escalate permissions in the Kubernetes cluster (Manual)"
category: cis-k8s
version: "1.12.0"
author: cyberstrike-official
tags: [cis, kubernetes, policies, rbac, service-accounts]
cis_id: "5.1.8"
cis_benchmark: "CIS Kubernetes Benchmark v1.12.0"
tech_stack: [kubernetes]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# 5.1.8 Limit use of the Bind, Impersonate and Escalate permissions in the Kubernetes cluster (Manual)

## Profile Applicability

- Level 1 - Master Node

## Description

Cluster roles and roles with the impersonate, bind or escalate permissions should not be granted unless strictly required. Each of these permissions allow a particular subject to escalate their privileges beyond those explicitly granted by cluster administrators.

## Rationale

The impersonate privilege allows a subject to impersonate other users gaining their rights to the cluster. The bind privilege allows the subject to add a binding to a cluster role or role which escalates their effective permissions in the cluster. The escalate privilege allows a subject to modify cluster roles to which they are bound, increasing their rights to that level.

Each of these permissions has the potential to allow for privilege escalation to cluster-admin level.

## Impact

There are some cases where these permissions are required for cluster service operation, and care should be taken before removing these permissions from system service accounts.

## Audit Procedure

Review the users who have access to cluster roles or roles which provide the impersonate, bind, or escalate privileges.

## Remediation

Where possible, remove the impersonate, bind, and escalate rights from subjects.

## Default Value

In a default kubeadm cluster, the system:masters group and clusterrole-aggregation-controller service account have access to the escalate privilege. The system:masters group also has access to bind and impersonate.

## References

1. https://raesene.github.io/blog/2020/12/12/Escalating_Away/
2. https://raesene.github.io/blog/2021/01/16/Getting-Into-A-Bind-with-Kubernetes/

## CIS Controls

| Controls Version | Control                                                                   | IG 1 | IG 2 | IG 3 |
| ---------------- | ------------------------------------------------------------------------- | ---- | ---- | ---- |
| v8               | 5.4 Restrict Administrator Privileges to Dedicated Administrator Accounts | X    | X    | X    |
| v7               | 4 Controlled Use of Administrative Privileges                             |      |      |      |