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package processing
// DCSO FEVER
// Copyright (c) 2018, 2020, DCSO GmbH
import (
"bufio"
"net"
"os"
"sync"
"github.com/DCSO/fever/types"
"github.com/DCSO/fever/util"
log "github.com/sirupsen/logrus"
"github.com/yl2chen/cidranger"
)
// IPAlertJSONProviderSrcIP is an AlertJSONProvider for source IP address matches.
type IPAlertJSONProviderSrcIP struct{}
// GetAlertJSON returns the "alert" subobject for an alert EVE event.
func (a IPAlertJSONProviderSrcIP) GetAlertJSON(inputEvent types.Entry,
prefix string, ioc string) ([]byte, error) {
return util.GenericGetAlertObjForIoc(inputEvent, prefix, ioc,
"%s Communication involving IP "+inputEvent.SrcIP+" in listed range %s")
}
// IPAlertJSONProviderDstIP is an AlertJSONProvider for destination IP address
// matches.
type IPAlertJSONProviderDstIP struct{}
// GetAlertJSON returns the "alert" subobject for an alert EVE event.
func (a IPAlertJSONProviderDstIP) GetAlertJSON(inputEvent types.Entry,
prefix string, ioc string) ([]byte, error) {
return util.GenericGetAlertObjForIoc(inputEvent, prefix, ioc,
"%s Communication involving IP "+inputEvent.DestIP+" in listed range %s")
}
// IPHandler is a Handler which is meant to check for the presence of
// event type-specific keywords in a Bloom filter, raising new 'alert' type
// events when matches are found.
type IPHandler struct {
sync.Mutex
Logger *log.Entry
Name string
EventType string
Ranger cidranger.Ranger
IPListFilename string
DatabaseEventChan chan types.Entry
ForwardHandler Handler
AlertPrefix string
Alertifier *util.Alertifier
}
// MakeIPHandler returns a new IPHandler, checking against the given
// IP ranges and sending alerts to databaseChan as well as forwarding them
// to a given forwarding handler.
func MakeIPHandler(ranger cidranger.Ranger,
databaseChan chan types.Entry, forwardHandler Handler,
alertPrefix string) *IPHandler {
ih := &IPHandler{
Logger: log.WithFields(log.Fields{
"domain": "ip-blacklist",
}),
Ranger: ranger,
DatabaseEventChan: databaseChan,
ForwardHandler: forwardHandler,
AlertPrefix: alertPrefix,
Alertifier: util.MakeAlertifier(alertPrefix),
}
ih.Alertifier.SetExtraModifier(bloomExtraModifier)
ih.Alertifier.RegisterMatchType("ip-src", IPAlertJSONProviderSrcIP{})
ih.Alertifier.RegisterMatchType("ip-dst", IPAlertJSONProviderDstIP{})
ih.Alertifier.SetExtraModifier(nil)
log.WithFields(log.Fields{}).Info("IP range list loaded")
return ih
}
func rangerFromFile(IPListFilename string) (cidranger.Ranger, error) {
inFile, err := os.Open(IPListFilename)
if err != nil {
return nil, err
}
defer inFile.Close()
ranger := cidranger.NewPCTrieRanger()
scanner := bufio.NewScanner(inFile)
scanner.Split(bufio.ScanLines)
for scanner.Scan() {
lineText := scanner.Text()
_, network, err := net.ParseCIDR(lineText)
if err != nil {
log.Warnf("invalid IP range %s, skipping", lineText)
} else {
log.Debugf("adding IP range %s", lineText)
ranger.Insert(cidranger.NewBasicRangerEntry(*network))
}
}
return ranger, nil
}
// MakeIPHandlerFromFile returns a new IPHandler created from a new
// IP range list specified by the given file name.
func MakeIPHandlerFromFile(IPListFilename string,
databaseChan chan types.Entry, forwardHandler Handler, alertPrefix string) (*IPHandler, error) {
ranger, err := rangerFromFile(IPListFilename)
if err != nil {
return nil, err
}
ih := MakeIPHandler(ranger, databaseChan, forwardHandler, alertPrefix)
ih.IPListFilename = IPListFilename
return ih, nil
}
// Reload triggers a reload of the contents of the IP list file.
func (a *IPHandler) Reload() error {
ranger, err := rangerFromFile(a.IPListFilename)
if err != nil {
return err
}
a.Lock()
a.Ranger = ranger
a.Unlock()
return nil
}
// Consume processes an Entry, emitting alerts if there is a match
func (a *IPHandler) Consume(e *types.Entry) error {
a.Lock()
srcRanges, err := a.Ranger.ContainingNetworks(net.ParseIP(e.SrcIP))
if err != nil {
log.Warn(err)
}
for _, v := range srcRanges {
matchedNet := v.Network()
matchedNetString := matchedNet.String()
if n, err := a.Alertifier.MakeAlert(*e, matchedNetString, "ip-src"); err == nil {
a.DatabaseEventChan <- *n
a.ForwardHandler.Consume(n)
} else {
log.Warn(err)
}
}
dstRanges, err := a.Ranger.ContainingNetworks(net.ParseIP(e.DestIP))
if err != nil {
log.Warn(err)
}
for _, v := range dstRanges {
matchedNet := v.Network()
matchedNetString := matchedNet.String()
if n, err := a.Alertifier.MakeAlert(*e, matchedNetString, "ip-dst"); err == nil {
a.DatabaseEventChan <- *n
a.ForwardHandler.Consume(n)
} else {
log.Warn(err)
}
}
a.Unlock()
return nil
}
// GetName returns the name of the handler
func (a *IPHandler) GetName() string {
return "IP blacklist handler"
}
// GetEventTypes returns a slice of event type strings that this handler
// should be applied to
func (a *IPHandler) GetEventTypes() []string {
return []string{"http", "dns", "tls", "smtp", "flow", "ssh", "tls", "smb"}
}
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