Policy Examples for Nodes/VMs
Here, we demonstrate how to define host security policies.
- Process Execution Restriction
- apiVersion: security.kubearmor.com/v1kind: KubeArmorHostPolicymetadata:name: hsp-kubearmor-dev-proc-path-blockspec:nodeSelector:matchLabels:kubernetes.io/hostname: kubearmor-devseverity: 5process:matchPaths:- path: /usr/bin/diffaction: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.
NOTEThe 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 ofsleep
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
- apiVersion: security.kubearmor.com/v1kind: KubeArmorHostPolicymetadata:name: hsp-kubearmor-dev-file-path-auditspec:nodeSelector:matchLabels:kubernetes.io/hostname: kubearmor-devseverity: 5file:matchPaths:- path: /etc/passwdaction: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/v1kind: KubeArmorHostPolicymetadata:name: audit-all-unlinkspec:severity: 3nodeSelector:matchLabels:kubernetes.io/hostname: vagrantsyscalls:matchSyscalls:- syscall:- unlinkaction:Audit
{
"Timestamp": 1661937152,
"UpdatedTime": "2022-08-31T09:12:32.967304Z",
"ClusterName": "default",
"HostName": "vagrant",
"HostPPID": 8563,
"HostPID": 310459,
"PPID": 8563,
"PID": 310459,
"UID": 1000,
"ProcessName": "/usr/bin/unlink",
"PolicyName": "audit-all-unlink",
"Severity": "3",
"Type": "MatchedHostPolicy",
"Source": "/usr/bin/unlink /home/vagrant/secret.txt",
"Operation": "Syscall",
"Resource": "/home/vagrant/secret.txt",
"Data": "syscall=SYS_UNLINK",
"Action": "Audit",
"Result": "Passed"
}
- 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
{
"Timestamp": 1661936983,
"UpdatedTime": "2022-08-31T09:09:43.894787Z",
"ClusterName": "default",
"HostName": "vagrant",
"HostPPID": 308001,
"HostPID": 308002,
"PPID": 308001,
"PID": 308002,
"ProcessName": "/usr/bin/rmdir",
"PolicyName": "audit-home-rmdir",
"Severity": "3",
"Type": "MatchedHostPolicy",
"Source": "/usr/bin/rmdir jane-doe",
"Operation": "Syscall",
"Resource": "/home/jane-doe",
"Data": "syscall=SYS_RMDIR",
"Action": "Audit",
"Result": "Passed"
}
Last modified 8mo ago