What is this all about?
A recent CVE targeting Polyfill.io has surfaced, impacting many companies and highlighting a vulnerability that could potentially affect others through similar attack methods.
Polyfill.io is a widely-used JavaScript library and service that enhances compatibility by adding support for newer JavaScript features and browser APIs to older browsers. Websites typically integrate Polyfill by including a JavaScript tag in their HTML.
According to The Register “The polyfill.io domain is being used to infect more than 100,000 websites with malicious code after what's said to be a Chinese organization bought the domain earlier this year, researchers have said.”
How CVE-2024-38526 Supply Chain Attacks Could Impact Your Kubernetes (K8s) Infrastructure
Here are several points on how a supply chain attack like CVE-2024-38526 could potentially affect your Kubernetes (K8s) infrastructure:
- Container image compromise: When a malicious polyfill is included in container images, it becomes part of the application running in K8s pods. This could allow attackers to execute arbitrary code within the container, potentially leading to data theft, lateral movement, or even escape from the container to the host system.
- Dependency vulnerabilities: Kubernetes itself and many of its supporting tools are written in languages that often use polyfills or similar libraries. If a core K8s component (like the API server, scheduler, or controller manager) incorporates a vulnerable library, it could lead to cluster-wide compromise.
- CI/CD pipeline infection: Modern K8s deployments often rely on automated CI/CD pipelines. If the build process or deployment scripts incorporate the vulnerable polyfill, it could lead to widespread infection across multiple applications and environments.
- Admission controller bypass: Sophisticated malicious code might be able to exploit vulnerabilities to bypass security controls implemented by admission controllers, potentially allowing the deployment of unauthorized or malicious workloads.
- Service mesh compromise: In a microservices architecture using a service mesh (like Istio or Linkerd), a compromised component could intercept or manipulate traffic between services, leading to data breaches or service disruptions.
- Kubernetes-specific attack vectors: Attackers could target K8s-specific components like the kubelet, kube-proxy, or CustomResourceDefinitions (CRDs) to gain elevated privileges or manipulate cluster behavior.
- Supply chain poisoning of Kubernetes distributions: If the vulnerability affects a popular K8s distribution or installer, it could lead to compromised clusters right from the initial setup.
- Exploitation of Kubernetes ecosystem tools: Many organizations use third-party tools for monitoring, logging, or security in their K8s environments. If these tools are affected, it could provide attackers with a foothold in the cluster.
- Impact on multi-tenant clusters: In shared Kubernetes environments, a supply chain attack could potentially lead to cross-tenant data access or resource abuse.
- Long-term persistence: Sophisticated attackers might use the initial access gained through the supply chain attack to establish long-term persistence in the cluster, possibly by creating backdoored CronJobs or DaemonSets.
How to mitigate these risks
To mitigate these risks, organizations should:
- Regularly scan container images and dependencies for vulnerabilities
- Implement strict supply chain security measures (e.g., software bill of materials, signed images)
- Use runtime security tools to detect anomalous behavior in K8s clusters
- Follow the principle of least privilege for all cluster components and workloads
- Keep Kubernetes and all related tools up-to-date with security patches
Reach out to us at KTrust if you’d like a free assessment to see if you have any impacted assets.
