Argo Events is an event-driven workflow automation framework for Kubernetes. A user with permission to create/modify EventSource and Sensor custom resources can gain privileged access to the host system and cluster, even without having direct administrative privileges. The EventSource and Sensor CRs allow the corresponding orchestrated pod to be customized with spec.template and spec.template.container (with type k8s.io/api/core/v1.Container), thus, any specification under container such as command, args, securityContext , volumeMount can be specified, and applied to the EventSource or Sensor pod. With these, a user would be able to gain privileged access to the cluster host, if he/she specified the EventSource/Sensor CR with some particular properties under template. This vulnerability is fixed in v1.9.6.
The product performs an operation at a privilege level that is higher than the minimum level required, which creates new weaknesses or amplifies the consequences of other weaknesses.
New weaknesses can be exposed because running with extra privileges, such as root or Administrator, can disable the normal security checks being performed by the operating system or surrounding environment. Other pre-existing weaknesses can turn into security vulnerabilities if they occur while operating at raised privileges. Privilege management functions can behave in some less-than-obvious ways, and they have different quirks on different platforms. These inconsistencies are particularly pronounced if you are transitioning from one non-root user to another. Signal handlers and spawned processes run at the privilege of the owning process, so if a process is running as root when a signal fires or a sub-process is executed, the signal handler or sub-process will operate with root privileges.