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.
Continue readingMisc
Methodology for Assessing Kubernetes Namespace-Based Multi-Tenancy Setups
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.
Continue readingSecurity Considerations on Istio’s CRDs with Namespace-based Multi-Tenancy
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).
In collaboration with Istio, we published a guest submission in Istio’s blog (as well as below), a Security Bulletin, and an update to their Security Model to address this issue.
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.
Continue readingAssessing Endpoint Protection: Our Approach to EDR/XDR and Supplements Evaluation
There is a growing landscape of security products promising to protect an organization’s IT infrastructure from attacks. Solutions referred to as EDR, and sometimes also as XDR, are designed to protect endpoints from all malicious activity. The ever-increasing cases of breaches and the associated costs, especially in the realm of ransomware attacks, raise the question of whether there is more that can be done to add an additional layer to traditional endpoint protection concepts. That is why a customer of ours commissioned us to evaluate whether EDR supplementing solutions provide extended protection against ever-evolving threats, as well as to shine a light on the performance overheads those solutions might introduce.
Continue readingCapture Bumble Bluetooth Traffic with Wireshark
When conducting pentests of Bluetooth devices or whilst working on Bluetooth related research, we often use Bumble. In this Blogpost I will present a solution to capture a live stream of Bumble Bluetooth traffic in Wireshark.
Bumble is a fully featured Bluetooth stack, written entirely in Python. What makes it extremely powerful for security assessments and research is the level of control it provides. It can simulate certain conditions, including errors, with a level of precision that most Bluetooth stacks don’t offer. However, sometimes you not only need control, you also need visibility.
Continue readingIncident Response in GCP: Out of Scope – Out of Mind
We are regularly offering a GCP Incident Response and Analysis training. In this training, we analyze resources in GCP cloud together with our trainees that were successfully compromised by attackers, e.g., GCE instances and Cloud Build projects. Therefore, we need tooling that quickly detects misconfiguration of resources that helped the attacker during the compromise. During the analysis of different tools and different kinds of misconfiguration we realized that GCE instance access scopes are a blind spot of many (in fact all that we tested) security audit tools. In this blog post, we want to elaborate on the problems that arise from this behavior.
Continue readingBluetooth Headphone Jacking: Full Disclosure of Airoha RACE Vulnerabilities
About six months ago we released a security advisory on this blog about vulnerabilities in Airoha-based Bluetooth headphones and earbuds. Back then, we didn’t release all technical details to give vendors more time to release updates and users time to patch their devices. Around the time of the initial partial disclosure in the beginning of June, Airoha put out an SDK release for their customers that mitigates the vulnerabilities. Now, half a year later, we finally want to publish the technical details and release a tool for researchers and users to continue researching and check whether their devices are vulnerable.
Continue readingWindows Hello for Business – Past and Present Attacks
Windows Hello for Business is a key component of Microsoft’s passwordless authentication strategy. It enables user authentication not only during system sign-in but also in conjunction with new and advanced features such as Personal Data Encryption, Administrator Protection, and Recall. Rather than depending on traditional passwords, Windows Hello leverages a PIN or biometric methods – such as fingerprint or facial recognition – to unlock cryptographic keys protected by the Trusted Platform Module (TPM).
Continue readingUsing the Raspberry Pi Pico W as a Bluetooth Dongle
During our recent research, we experimented with different Bluetooth USB dongles. There are tons of options, and sometimes, it’s challenging to determine what chipset a dongle actually contains, what Bluetooth features it supports, and whether it works on Linux. Inspired by the recent ESP32 Bluetooth research, we wondered whether we could turn our Raspberry Pi Pico Ws into a functioning Bluetooth dongle. We had a few lying around, and the advantage here is that we know exactly which Bluetooth controller it uses – the Infineon CYW43439. It’s also very easy to get one. You can just buy the Pico W for a few bucks, even cheaper than some Bluetooth dongles. You also have a controller family that has been researched quite a bit in the internalblue project. However, there was one disadvantage. We did not find any code that exposes the CYW43439’s HCI interface via USB. So we had to write that on our own.
Continue readingWhen Your Edge Browser Syncs Private Data to Your Employer
Recently, one of our customers contacted us to investigate the extent of some unwanted and unexpected behavior regarding browsing data of employees.
Employees started contacting IT support because private browser bookmarks, private login credentials etc. showed up on their work machines. All affected employees stated that they never created these bookmarks on work systems. And interestingly, the data seemed to have been collected over quite some time.
Our customer wanted to understand how private data ended up in their environment. Obviously, private employee data in the enterprise landscape could cause some data privacy trouble (GDPR).
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