[Filebeat] Add network.direction to netflow/log fileset

CHANGELOG.next.asciidoc

@@ -757,6 +757,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Migrate microsoft/m365_defender to httpjson v2 config {pull}23018[23018]
 - Add top_level_domain enrichment for suricata/eve fileset. {pull}23046[23046]
 - Add top_level_domain enrichment for zeek/dns fileset. {pull}23046[23046]
+- Add `network.direction` to netflow/log fileset. {pull}23052[23052]
 
 *Heartbeat*
 

x-pack/filebeat/filebeat.reference.yml

@@ -1370,6 +1370,11 @@ filebeat.modules:
     var:
       netflow_host: localhost
       netflow_port: 2055
+      # internal_networks specifies which networks are considered internal or private
+      # you can specify either a CIDR block or any of the special named ranges listed
+      # at: https://www.elastic.co/guide/en/beats/filebeat/current/defining-processors.html#condition-network
+      internal_networks:
+        - private
 
 #-------------------------- Arbor Peakflow SP Module --------------------------
 - module: netscout

x-pack/filebeat/input/netflow/config.go

@@ -16,6 +16,7 @@ import (
 type config struct {
 	udp.Config                `config:",inline"`
 	harvester.ForwarderConfig `config:",inline"`
+	InternalNetworks          []string      `config:"internal_networks"`
 	Protocols                 []string      `config:"protocols"`
 	ExpirationTimeout         time.Duration `config:"expiration_timeout"`
 	PacketQueueSize           int           `config:"queue_size"`

x-pack/filebeat/input/netflow/convert.go

@@ -17,6 +17,7 @@ import (
 	"github.com/elastic/beats/v7/libbeat/beat"
 	"github.com/elastic/beats/v7/libbeat/common"
 	"github.com/elastic/beats/v7/libbeat/common/flowhash"
+	"github.com/elastic/beats/v7/libbeat/conditions"
 	"github.com/elastic/beats/v7/x-pack/filebeat/input/netflow/decoder/record"
 )
 
@@ -35,10 +36,10 @@ var (
 	}
 )
 
-func toBeatEvent(flow record.Record) (event beat.Event) {
+func toBeatEvent(flow record.Record, internalNetworks []string) (event beat.Event) {
 	switch flow.Type {
 	case record.Flow:
-		return flowToBeatEvent(flow)
+		return flowToBeatEvent(flow, internalNetworks)
 	case record.Options:
 		return optionsToBeatEvent(flow)
 	default:
@@ -113,7 +114,7 @@ func optionsToBeatEvent(flow record.Record) beat.Event {
 	return toBeatEventCommon(flow)
 }
 
-func flowToBeatEvent(flow record.Record) (event beat.Event) {
+func flowToBeatEvent(flow record.Record, internalNetworks []string) (event beat.Event) {
 	event = toBeatEventCommon(flow)
 
 	ecsEvent, ok := event.Fields["event"].(common.MapStr)
@@ -179,12 +180,12 @@ func flowToBeatEvent(flow record.Record) (event beat.Event) {
 			}
 			if srcIP != nil {
 				ecsSource["ip"] = srcIP
-				ecsSource["locality"] = getIPLocality(srcIP).String()
+				ecsSource["locality"] = getIPLocality(internalNetworks, srcIP).String()
 			}
 			ecsSource["mac"] = srcMac
 			if dstIP != nil {
 				ecsDest["ip"] = dstIP
-				ecsDest["locality"] = getIPLocality(dstIP).String()
+				ecsDest["locality"] = getIPLocality(internalNetworks, dstIP).String()
 			}
 			ecsDest["mac"] = dstMac
 		}
@@ -194,7 +195,7 @@ func flowToBeatEvent(flow record.Record) (event beat.Event) {
 	if ip, found := getKeyIP(flow.Fields, "sourceIPv4Address"); found {
 		ecsSource["ip"] = ip
 		relatedIP = append(relatedIP, ip)
-		ecsSource["locality"] = getIPLocality(ip).String()
+		ecsSource["locality"] = getIPLocality(internalNetworks, ip).String()
 	}
 	if sourcePort, found := getKeyUint64(flow.Fields, "sourceTransportPort"); found {
 		ecsSource["port"] = sourcePort
@@ -207,7 +208,7 @@ func flowToBeatEvent(flow record.Record) (event beat.Event) {
 	if ip, found := getKeyIP(flow.Fields, "destinationIPv4Address"); found {
 		ecsDest["ip"] = ip
 		relatedIP = append(relatedIP, ip)
-		ecsDest["locality"] = getIPLocality(ip).String()
+		ecsDest["locality"] = getIPLocality(internalNetworks, ip).String()
 	}
 	if destPort, found := getKeyUint64(flow.Fields, "destinationTransportPort"); found {
 		ecsDest["port"] = destPort
@@ -243,7 +244,7 @@ func flowToBeatEvent(flow record.Record) (event beat.Event) {
 		dstIP = net.IPv4(0, 0, 0, 0).To4()
 	}
 	ecsFlow["id"] = flowID(srcIP, dstIP, srcPort, dstPort, uint8(protocol))
-	ecsFlow["locality"] = getIPLocality(srcIP, dstIP).String()
+	ecsFlow["locality"] = getIPLocality(internalNetworks, srcIP, dstIP).String()
 
 	// ECS Fields -- network
 	ecsNetwork := common.MapStr{}
@@ -394,29 +395,23 @@ func (l Locality) String() string {
 	return "unknown (" + strconv.Itoa(int(l)) + ")"
 }
 
-func isPrivateNetwork(ip net.IP) bool {
-	for _, net := range privateIPv4 {
-		if net.Contains(ip) {
-			return true
-		}
-	}
-
-	return privateIPv6.Contains(ip)
-}
-
-func isLocalOrPrivate(ip net.IP) bool {
-	return isPrivateNetwork(ip) ||
-		ip.IsLoopback() ||
+func isLocal(ip net.IP) bool {
+	return ip.IsLoopback() ||
 		ip.IsUnspecified() ||
 		ip.Equal(net.IPv4bcast) ||
 		ip.IsLinkLocalUnicast() ||
 		ip.IsLinkLocalMulticast() ||
 		ip.IsInterfaceLocalMulticast()
 }
 
-func getIPLocality(ip ...net.IP) Locality {
-	for _, addr := range ip {
-		if !isLocalOrPrivate(addr) {
+func getIPLocality(internalNetworks []string, ips ...net.IP) Locality {
+	for _, ip := range ips {
+		contains, err := conditions.NetworkContains(ip, internalNetworks...)
+		if err != nil {
+			return LocalityPublic
+		}
+		// always consider loopback/link-local private
+		if !contains && !isLocal(ip) {
 			return LocalityPublic
 		}
 	}

x-pack/filebeat/input/netflow/input.go

@@ -45,15 +45,16 @@ type packet struct {
 }
 
 type netflowInput struct {
-	mutex     sync.Mutex
-	udp       *udp.Server
-	decoder   *decoder.Decoder
-	outlet    channel.Outleter
-	forwarder *harvester.Forwarder
-	logger    *logp.Logger
-	queueC    chan packet
-	queueSize int
-	started   bool
+	mutex            sync.Mutex
+	udp              *udp.Server
+	decoder          *decoder.Decoder
+	outlet           channel.Outleter
+	forwarder        *harvester.Forwarder
+	internalNetworks []string
+	logger           *logp.Logger
+	queueC           chan packet
+	queueSize        int
+	started          bool
 }
 
 func init() {
@@ -122,11 +123,12 @@ func NewInput(
 	}
 
 	input := &netflowInput{
-		outlet:    out,
-		forwarder: harvester.NewForwarder(out),
-		decoder:   decoder,
-		logger:    logger,
-		queueSize: config.PacketQueueSize,
+		outlet:           out,
+		internalNetworks: config.InternalNetworks,
+		forwarder:        harvester.NewForwarder(out),
+		decoder:          decoder,
+		logger:           logger,
+		queueSize:        config.PacketQueueSize,
 	}
 
 	input.udp = udp.New(&config.Config, input.packetDispatch)
@@ -243,7 +245,7 @@ func (p *netflowInput) recvRoutine() {
 			evs := make([]beat.Event, n)
 			numFlows.Add(uint64(n))
 			for i, flow := range flows {
-				evs[i] = toBeatEvent(flow)
+				evs[i] = toBeatEvent(flow, p.internalNetworks)
 			}
 			p.Publish(evs)
 		}

x-pack/filebeat/input/netflow/netflow_test.go

@@ -197,7 +197,7 @@ func getFlowsFromDat(t testing.TB, name string, testCase TestCase) TestResult {
 			}
 			ev := make([]beat.Event, len(flows))
 			for i := range flows {
-				ev[i] = toBeatEvent(flows[i])
+				ev[i] = toBeatEvent(flows[i], []string{"private"})
 			}
 			//return TestResult{Name: name, Error: err.Error(), Events: flowsToEvents(flows)}
 			events = append(events, ev...)
@@ -242,7 +242,7 @@ func getFlowsFromPCAP(t testing.TB, name, pcapFile string) TestResult {
 		}
 		ev := make([]beat.Event, len(flows))
 		for i := range flows {
-			ev[i] = toBeatEvent(flows[i])
+			ev[i] = toBeatEvent(flows[i], []string{"private"})
 		}
 		events = append(events, ev...)
 	}
@@ -341,7 +341,7 @@ func TestReverseFlows(t *testing.T) {
 
 	var evs []beat.Event
 	for _, f := range flows {
-		evs = append(evs, toBeatEvent(f))
+		evs = append(evs, toBeatEvent(f, []string{"private"}))
 	}
 	if !assert.Len(t, evs, 2) {
 		t.Fatal()

x-pack/filebeat/module/netflow/_meta/config.yml

@@ -4,3 +4,8 @@
     var:
       netflow_host: localhost
       netflow_port: 2055
+      # internal_networks specifies which networks are considered internal or private
+      # you can specify either a CIDR block or any of the special named ranges listed
+      # at: https://www.elastic.co/guide/en/beats/filebeat/current/defining-processors.html#condition-network
+      internal_networks:
+        - private

x-pack/filebeat/module/netflow/log/config/netflow.yml

@@ -5,6 +5,13 @@ max_message_size: '{{.max_message_size}}'
 expiration_timeout: '{{.expiration_timeout}}'
 queue_size: {{.queue_size}}
 
+{{if .internal_networks}}
+internal_hosts:
+{{range .internal_networks}}
+- '{{ . }}'
+{{end}}
+{{end}}
+
 {{if .timeout}}
 timeout: '{{.timeout}}'
 {{end}}

x-pack/filebeat/module/netflow/log/ingest/pipeline.yml

@@ -51,6 +51,26 @@ processors:
         field: destination.as.organization_name
         target_field: destination.as.organization.name
         ignore_missing: true
+  - set:
+        field: network.direction
+        value: inbound
+        if: 'ctx?.source?.locality == "external" && ctx?.destination?.locality == "internal"'
+  - set:
+        field: network.direction
+        value: outbound
+        if: 'ctx?.source?.locality == "internal" && ctx?.destination?.locality == "external"'
+  - set:
+        field: network.direction
+        value: internal
+        if: 'ctx?.source?.locality == "internal" && ctx?.destination?.locality == "internal"'
+  - set:
+        field: network.direction
+        value: external
+        if: 'ctx?.source?.locality == "external" && ctx?.destination?.locality == "external"'
+  - set:
+        field: network.direction
+        value: unknown
+        if: 'ctx?.network?.direction == null'
 
 on_failure:
   - set:

x-pack/filebeat/modules.d/netflow.yml.disabled

@@ -7,3 +7,8 @@
     var:
       netflow_host: localhost
       netflow_port: 2055
+      # internal_networks specifies which networks are considered internal or private
+      # you can specify either a CIDR block or any of the special named ranges listed
+      # at: https://www.elastic.co/guide/en/beats/filebeat/current/defining-processors.html#condition-network
+      internal_networks:
+        - private