Policy Examples for Nodes/VMs
Here, we demonstrate how to define host security policies.
Process Execution Restriction
Block a specific executable (hsp-kubearmor-dev-proc-path-block.yaml)
apiVersion: security.kubearmor.com/v1 kind: KubeArmorHostPolicy metadata: name: hsp-kubearmor-dev-proc-path-block spec: nodeSelector: matchLabels: kubernetes.io/hostname: kubearmor-dev severity: 5 process: matchPaths: - path: /usr/bin/diff action: Block
Explanation: The purpose of this policy is to block the execution of '/usr/bin/diff' in a host whose host name is 'kubearmor-dev'. For this, we define 'kubernetes.io/hostname: kubearmor-dev' in nodeSelector -> matchLabels and the specific path ('/usr/bin/diff') in process -> matchPaths. Also, we put 'Block' as the action of this policy.
Verification: After applying this policy, please open a new terminal (or connect to the host with a new session) and run '/usr/bin/diff'. You will see that /usr/bin/diff is blocked.
NOTE
The given policy works with almost every linux distribution. If it is not working in your case, check the process location. The following location shows location of
sleep
binary in different ubuntu distributions:In case of Ubuntu 20.04 : /usr/bin/sleep
In case of Ubuntu 18.04 : /bin/sleep
File Access Restriction
Audit a critical file access (hsp-kubearmor-dev-file-path-audit.yaml)
apiVersion: security.kubearmor.com/v1 kind: KubeArmorHostPolicy metadata: name: hsp-kubearmor-dev-file-path-audit spec: nodeSelector: matchLabels: kubernetes.io/hostname: kubearmor-dev severity: 5 file: matchPaths: - path: /etc/passwd action: Audit
Explanation: The purpose of this policy is to audit any accesses to a critical file (i.e., '/etc/passwd'). Since we want to audit one critical file, we use matchPaths to specify the path of '/etc/passwd'.
Verification: After applying this policy, please open a new terminal (or connect to the host with a new session) and run 'sudo cat /etc/passwd'. Then, check the alert logs of KubeArmor.
System calls alerting
Alert for all
unlink
syscalls
apiVersion: security.kubearmor.com/v1 kind: KubeArmorHostPolicy metadata: name: audit-all-unlink spec: severity: 3 nodeSelector: matchLabels: kubernetes.io/hostname: vagrant syscalls: matchSyscalls: - syscall: - unlink action: Audit
Alert on all
rmdir
syscalls targeting anything in/home/
directory and sub-directories
apiVersion: security.kubearmor.com/v1
kind: KubeArmorHostPolicy
metadata:
name: audit-home-rmdir
spec:
severity: 3
nodeSelector:
matchLabels:
kubernetes.io/hostname: vagrant
syscalls:
matchPaths:
- syscall:
- rmdir
path: /home/
recursive: true
action:
Audit
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