In our presentation, we explored the security challenges of namespace-based multi-tenancy in Kubernetes. We demonstrated real-world attacks against Kubeflow, Istio, and Traefik that can break the intended isolation between namespaces and workloads. One of the highlights was demonstrating a privilege-escalation attack we discovered that allowed us to gain cluster-admin privileges.
Kubeflow is vulnerable to the theft of authorization tokens by any user of the
Kubeflow UI or APIs, such as the Dashboard, Pipelines API, or Notebooks. With
this token, the attacker can take over the user’s account and the data that is
processed by that user. The attacker needs a valid user with the kubeflow-edit
or Contributor role in a random Kubeflow namespace to perform this attack. This
is given if Automatic Profile Creation is enabled. A setup based on the
official manifests prior to version 1.10, and on most other packaged Kubeflow
distributions, is vulnerable.
The Istio edit permissions were removed by Kubeflow in a timely manner. Affected
users should update to the latest version to mitigate this issue.
Exactly one week ago, Sven and I had the incredible opportunity to give our very
first talk at KubeCon + CloudNativeCon
2026: How To Break Multi-Tenancy Again and Again …and What We Can Learn From It.
We discussed the challenges of namespace-based multi-tenancy and presented
real-world exploits in
Kubeflow, Istio,
and Traefik that bypass threat boundaries between namespaces and workloads.
Based on these problems, we developed a methodology to assess and address them.
You can find the methodology discussed in the talk in
detail in another blog post or
on GitHub. You can also find the
slides here.
This page introduces our structured methodology for assessing security risks in
Kubernetes environments that use Namespace-based Multi-Tenancy. It addresses
weaknesses that break Namespace-based isolation that not well studied, yet. We
found this issues during our research and presented them together with this
methodology in our
Talk at KubeCon + CloudNativeCon Europe 2026.
The methodology assumes that industry best practices, such as NetworkPolicies,
Role-Based Access Control (RBAC), and Pod Security Standards, are already in
place. These measures provide a necessary baseline level of protection against
well-known isolation threats. However, they are insufficient to address a class
of more subtle attack vectors arising from interactions between tenants and
shared components. Such attack vectors may still compromise the confidentiality,
integrity, and availability (CIA) of the cluster and its workloads, even in
well-hardened environments.
We reported a possible Man-in-the-Middle (MitM) attack scenario in which
a VirtualService can redirect or intercept traffic within the service mesh.
This affects Namespace-based Multi-Tenancy clusters where tenants have the
permissions to deploy Istio resources (networking.istio.io/v1).
This blog post highlights the risks of using Istio in multi-tenant clusters and
explains how users can mitigate these risks and safely operate Istio in their
deployments.
During a customer project, we identified privilege escalation vulnerabilities in
Broadcom VMware Aria Operations. It is possible to escalate the privileges of an
administrative vCenter user to an Aria administrator and take over systems
integrated in Aria. Meaning, the vCenter user can gain privileged access to
systems they have no access to. While both users might sound similarly
privileged, this is not true in most environments – especially not in complex
corporate environments: An insignificant vCenter user in a development
environment can take over all other vCenters in a complex corporate environment.
Hi there,
like in recent years the popular
Hacking 101 workshop
will take place on TROOPERS20, too! The workshop will give you an insight into
the hacking techniques required for penetration testing. These
techniques will cover various topics:
Information gathering
Network scanning
Web application hacking
Low-level exploitation
…and more!
During this workshop you will learn, step by step, a testing methodology
that applies to the majority of scenarios. So imagine you have to assess the
security of a system running on the Internet. How would you start? First,
you need a good understanding of the target, including running services or
related systems. Just scanning the target’s IP address will most likely not
reveal all relevant information you can get. In the information gathering step,
you will learn where you could find more relevant information than just a list
of open ports. A brief understanding of the target and it’s related
systems/services/applications will make scanning and identifying
vulnerabilities a lot easier and more effective. Then, the last step will be
the exploitation of the identified vulnerabilities, with the ultimate aim to
get access to the target system and pivot to other, probably internal,
systems and resources.
Hi there,
like in recent years the popular
Hacking 101 workshop
will take place on TROOPERS19, too! The workshop will give you an insight into
the hacking techniques required for penetration testing. These
techniques will cover various topics:
Information gathering
Network scanning
Web application hacking
Low-level exploitation
…and more!
During this workshop you will learn, step by step, a testing methodology
that applies to the majority of scenarios. So imagine you have to assess the
security of a system running on the Internet. How would you start? First,
you need a good understanding of the target, including running services or
related systems. Just scanning the target’s IP address will most likely not
reveal all relevant information you can get. In the information gathering step,
you will learn where you could find more relevant information than just a list
of open ports. A brief understanding of the target and it’s related
systems/services/applications will make scanning and identifying
vulnerabilities a lot easier and more effective. Then, the last step will be
the exploitation of the identified vulnerabilities, with the ultimate aim to
get access to the target system and pivot to other, probably internal,
systems and resources.
A while ago, we had to scan a mass amount of IPs within a project for a
customer. While it’s feasible to read the whole output of a Nmap scan if you
have just a few alive hosts, this was not possible anymore for this mass amount
of systems. We’ve started with a
masscan to scan all 2^16 ports
of the IP ranges and wanted to perform a more precise analysis of the alive
hosts (which had responded to at least one SYN packet) with Nmap. The result of
this scan grew to nearly a hundred megabyte and we now had to do an analysis of
which ports we had to look deeper into and which are intended to be open.
Hi there,
Like in recent years the popular
Hacking 101 workshop
will take place on TROOPERS17, too! The workshop will give attendees an insight
into the hacking techniques required for penetration testing. These
techniques will cover various topics:
information gathering
network scanning
web application hacking
low-level exploitation
…and more!
During this workshop you will learn, step by step, a testing methodology
that is applicable to the majority of scenarios. So imagine you have to
assess the security of a system running on the Internet. How would you
start? First, you need a good understanding about the target, including running
services or related systems. Just scanning an IP will most likely not reveal
a lot of information about the system. The gathered information may help you to
identify communication relations of services that could include vulnerabilities.
A brief understanding of the target and it’s related
systems/services/applications will make scanning and identifying
vulnerabilities a lot easier and more effective. Then, the last step will be
the exploitation of the identified vulnerabilities, with the ultimate aim to
get access to the target system and pivot to other, probably internal,
systems and resources.