github.com/khulnasoft-lab/defsec@v1.0.5-0.20230827010352-5e9f46893d95/rules/cloud/policies/azure/network/no_public_egress.go

package network

import (
	"github.com/khulnasoft-lab/defsec/internal/cidr"
	"github.com/khulnasoft-lab/defsec/internal/rules"
	"github.com/khulnasoft-lab/defsec/pkg/providers"
	"github.com/khulnasoft-lab/defsec/pkg/scan"
	"github.com/khulnasoft-lab/defsec/pkg/severity"
	"github.com/khulnasoft-lab/defsec/pkg/state"
)

var CheckNoPublicEgress = rules.Register(
	scan.Rule{
		AVDID:      "AVD-AZU-0051",
		Provider:   providers.AzureProvider,
		Service:    "network",
		ShortCode:  "no-public-egress",
		Summary:    "An outbound network security rule allows traffic to /0.",
		Impact:     "The port is exposed for egress to the internet",
		Resolution: "Set a more restrictive cidr range",
		Explanation: `Network security rules should not use very broad subnets.

Where possible, segments should be broken into smaller subnets.`,
		Links: []string{
			"https://docs.microsoft.com/en-us/azure/security/fundamentals/network-best-practices",
		},
		Terraform: &scan.EngineMetadata{
			GoodExamples:        terraformNoPublicEgressGoodExamples,
			BadExamples:         terraformNoPublicEgressBadExamples,
			Links:               terraformNoPublicEgressLinks,
			RemediationMarkdown: terraformNoPublicEgressRemediationMarkdown,
		},
		Severity: severity.Critical,
	},
	func(s *state.State) (results scan.Results) {
		for _, group := range s.Azure.Network.SecurityGroups {
			var failed bool
			for _, rule := range group.Rules {
				if rule.Outbound.IsFalse() || rule.Allow.IsFalse() {
					continue
				}
				for _, ip := range rule.DestinationAddresses {
					if cidr.IsPublic(ip.Value()) {
						failed = true
						results.Add(
							"Security group rule allows egress to public internet.",
							ip,
						)
					}
				}
			}
			if !failed {
				results.AddPassed(&group)
			}
		}
		return
	},
)