A freshly disclosed security vulnerability in the Kubernetes container engine CRI-O known as cr8escape could be exploited by an attacker to crack out of containers and receive root access to the host.
“Invocation of CVE-2022-0811 can let an attacker to complete a wide variety of actions on aims, which includes execution of malware, exfiltration of facts, and lateral movement across pods,” CrowdStrike researchers John Walker and Manoj Ahuje reported in an evaluation released this week.
A lightweight option to Docker, CRI-O is a container runtime implementation of the Kubernetes Container Runtime Interface (CRI) which is employed to pull container illustrations or photos from registries and start an Open up Container Initiative (OCI)-appropriate runtime these types of as runC to spawn and operate container procedures.
The vulnerability is rated 8.8 on the CVSS vulnerability scoring method and influences CRI-O versions 1.19 and later. Following liable disclosure, patches have been produced to tackle the flaw in version 1.23.2 shipped on March 15, 2022.
CVE-2022-0811 stems from a code improve introduced in variation1.19 to established kernel alternatives for a pod, ensuing in a situation wherever a poor actor with permissions to deploy a pod on a Kubernetes cluster making use of the CRI-O runtime can choose advantage of the “kernel.main_pattern” parameter to accomplish container escape and arbitrary code execution as root on any node in the cluster.
The parameter “kernel.core_sample” is employed to specify a sample identify for a main dump, which is a file that contains the memory snapshot of a software at a distinct time which is normally activated in response to unexpected crashes or when the course of action terminates abnormally.
“If the 1st character of the pattern is a ‘|’ [a pipe], the kernel will treat the rest of the sample as a command to run. The main dump will be composed to the conventional input of that program rather of to a file,” reads the Linux kernel documentation.
Thus, by location this alternative to stage to a destructive shell script and triggering a main dump, the vulnerability leads to the invocation of the script, efficiently reaching remote code execution and granting the adversary the ability to get in excess of the node.
“Kubernetes is not essential to invoke CVE-2022-8011,” the researchers pointed out. “An attacker on a device with CRI-O installed can use it to established kernel parameters all by by itself.”
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