Network policy does not restrict egress destinations Affecting Deployment service in Kubernetes
Severity Framework
CCSS (Common Configuration Scoring System) is a set of measures used to determine the severity of the rule.
Snyk CCSS
Rule category
Each rule is associated with a high-level category. For example IAM, Container, Monitoring, Logging, Network, etc.
Network/ Network
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CIS-Controls
- Snyk IDSNYK-CC-00628
- creditSnyk Research Team
Description
Improperly configured egress rules in Kubernetes can enable pods to send network traffic outside the cluster, potentially allowing for unauthorized data exfiltration.
How to fix?
Add specific to attributes to egress rules.
Example Configuration
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: default-deny-all-egress
spec:
podSelector: {}
egress:
- to:
ports:
- protocol: TCP
port: 53
- protocol: UDP
port: 53
policyTypes:
- Egress
Add specific to attributes to the spec.egress rules.
Example Configuration
resource "kubernetes_network_policy" "allowed" {
metadata {
name = "terraform-example-network-policy628"
namespace = "default"
}
spec {
pod_selector {
match_expressions {
key = "name"
operator = "In"
values = ["webfront", "api"]
}
}
ingress {
ports {
port = "http"
protocol = "TCP"
}
ports {
port = "8125"
protocol = "UDP"
}
from {
namespace_selector {
match_labels = {
name = "default"
}
}
}
from {
ip_block {
cidr = "10.0.0.0/8"
except = [
"10.0.0.0/24",
"10.0.1.0/24",
]
}
}
}
egress {
to {
ip_block {
cidr = "10.0.0.0/8"
}
}
}
policy_types = ["Ingress", "Egress"]
}
}