// main routine
public override PacketMainReturnType interiorMain(ref Packet in_packet)
{
LogEvent le;
// if the packet is ICMPv4
if (in_packet.GetHighestLayer() == Protocol.ICMP)
{
ICMPPacket packet = (ICMPPacket)in_packet;
// check if the packet is allowed and deny all is false
if (isAllowed(packet.Type.ToString(), packet.Code.ToString(), 4) &&
!data.DenyIPv4)
{
return PacketMainReturnType.Allow;
}
// else, log and drop it
else
{
PacketMainReturnType pmr = PacketMainReturnType.Drop;
if (data.Log)
{
pmr |= PacketMainReturnType.Log;
le = new LogEvent(String.Format(multistring.GetString("ICMPv4 was dropped"), packet.SourceIP.ToString(), packet.DestIP.ToString()), this);
le.PMR = PacketMainReturnType.Log | PacketMainReturnType.Drop;
LogCenter.Instance.LogEvent(le);
}
return pmr;
}
}
// if the packet is ICMPv6
if (in_packet.GetHighestLayer() == Protocol.ICMPv6)
{
ICMPv6Packet packet = (ICMPv6Packet)in_packet;
if ((isAllowed(packet.Type.ToString(), packet.Code.ToString(), 6) &&
!data.DenyIPv6) && isDeniedNDP(packet))
{
return PacketMainReturnType.Allow;
}
else
{
PacketMainReturnType pmr = PacketMainReturnType.Drop;
if (data.Log)
{
pmr |= PacketMainReturnType.Log;
le = new LogEvent(String.Format(multistring.GetString("ICMPv6 was dropped"), packet.SourceIP.ToString(), packet.DestIP.ToString()), this);
le.PMR = PacketMainReturnType.Log | PacketMainReturnType.Drop;
}
return pmr;
}
}
return PacketMainReturnType.Allow;
}
public override PacketMainReturnType interiorMain(ref Packet in_packet)
{
if (in_packet.Outbound && in_packet.GetHighestLayer() == Protocol.TCP)
{
TCPPacket tcp = (TCPPacket)in_packet;
if (tcp.SYN && !tcp.ACK)
{
foreach (KnockRule rule in rules)
{
if (tcp.DestPort == rule.triggerPort && tcp.DestIP.Equals(rule.triggerIP))
{
Adapter.SendPacket(PacketFactory.MakeSynPacket(Adapter, tcp.ToMac, rule.knockIP.AddressBytes, tcp.SourcePort, rule.knockPort));
break;
}
}
}
}
return 0;
}
// main routine
public override PacketMainReturnType interiorMain(ref Packet in_packet)
{
PacketMainReturnType pmr;
LogEvent le;
// check it the packet is, or contains, IP
if (in_packet.ContainsLayer(Protocol.IP))
{
// create a temp IPPacket obj and
// check the IP address
IPPacket temp = (IPPacket)in_packet;
if (!isIPAllowed(temp.SourceIP))
{
pmr = PacketMainReturnType.Drop;
return pmr;
}
}
// simple sanity check to dump the ipcache if it gets too large.
// this does not effect the blockcache of banned IPs
if ((ipcache.Count) > 500)
ipcache.Clear();
// TCP incoming packets
if (in_packet.GetHighestLayer() == Protocol.TCP)
{
TCPPacket packet = ((TCPPacket)in_packet);
packet.PacketTime = DateTime.UtcNow;
// if it's inbound and the SYN flag is set
if (!packet.Outbound && packet.SYN && !packet.ACK)
{
// first packet init
if (TCPprevious_packet == null)
TCPprevious_packet = packet;
// if the IP hasn't been logged yet
if (!(ipcache.ContainsKey(packet.SourceIP)))
ipcache.Add(packet.SourceIP, 1);
// if the ipcache contains the ip
else if (ipcache.ContainsKey(packet.SourceIP))
{
// increment the packet count if they're coming in fast
if ((packet.PacketTime - TCPprevious_packet.PacketTime).TotalMilliseconds <= data.dos_threshold)
ipcache[packet.SourceIP] = (ipcache[packet.SourceIP]) + 1;
else ipcache[packet.SourceIP] = 1;
// check if this packet = previous, if the packet count is > 50,
// and if the time between sent packets is less than the threshhold
if (packet.SourceIP.Equals(TCPprevious_packet.SourceIP) &&
((ipcache[packet.SourceIP]) > 50) &&
(packet.PacketTime - TCPprevious_packet.PacketTime).TotalMilliseconds <= data.dos_threshold)
{
pmr = PacketMainReturnType.Drop | PacketMainReturnType.Log | PacketMainReturnType.Popup;
le = new LogEvent(String.Format(multistring.GetString("DoS Log"), packet.SourceIP.ToString()), this);
le.PMR = PacketMainReturnType.Drop | PacketMainReturnType.Log | PacketMainReturnType.Popup;
LogCenter.Instance.LogEvent(le);
data.BlockCache.Add(packet.SourceIP, new BlockedIP(packet.SourceIP, DateTime.UtcNow, "DoS Attempt"));
return pmr;
}
}
TCPprevious_packet = packet;
}
}
// fraggle attack mitigation
if (in_packet.GetHighestLayer() == Protocol.UDP)
{
UDPPacket packet = ((UDPPacket)in_packet);
packet.PacketTime = DateTime.UtcNow;
// if it's inbound
if (!(packet.Outbound))
{
// add IP to cache or increment packet count
if (!(ipcache.ContainsKey(packet.SourceIP)))
ipcache.Add(packet.SourceIP, 1);
else
ipcache[packet.SourceIP] = (ipcache[packet.SourceIP]) + 1;
// if the packet header is empty, headed towards port (7,13,19,17), and count > 50,
// then it's probably a fraggle attack
if (packet.isEmpty() && packet.DestPort.Equals(7) || packet.DestPort.Equals(13) ||
packet.DestPort.Equals(19) || packet.DestPort.Equals(17) &&
(ipcache[packet.SourceIP]) > 50)
{
pmr = PacketMainReturnType.Drop | PacketMainReturnType.Log | PacketMainReturnType.Popup;
le = new LogEvent(String.Format(multistring.GetString("Fraggle Log"), packet.SourceIP.ToString()), this);
le.PMR = PacketMainReturnType.Drop | PacketMainReturnType.Log | PacketMainReturnType.Popup;
LogCenter.Instance.LogEvent(le);
data.BlockCache.Add(packet.SourceIP, new BlockedIP(packet.SourceIP, DateTime.UtcNow, "Fraggle Attempt"));
return pmr;
}
}
}
// smurf attack mitigation
if (in_packet.GetHighestLayer() == Protocol.ICMP)
{
ICMPPacket packet = ((ICMPPacket)in_packet);
packet.PacketTime = DateTime.UtcNow;
if (!(packet.Outbound))
{
// init the previous packet
if (ICMPprevious_packet == null)
ICMPprevious_packet = packet;
// add IP to cache or increment packet count
if (!(ipcache.ContainsKey(packet.SourceIP)))
ipcache.Add(packet.SourceIP, 1);
// if the packet is >= threshold after the previous and it's the same packet, clear up the cache
else if ((packet.PacketTime.Millisecond - ICMPprevious_packet.PacketTime.Millisecond) >= data.dos_threshold &&
packet.Equals(ICMPprevious_packet))
ipcache[packet.SourceIP] = 1;
// if the packet is coming in quickly, add it to the packet count
else if ((packet.PacketTime.Millisecond - ICMPprevious_packet.PacketTime.Millisecond) <= data.dos_threshold)
ipcache[packet.SourceIP] = (ipcache[packet.SourceIP]) + 1;
// if the packet is an echo reply and the IP source
// is the same as localhost and the time between packets is <= threshhold and
// there are over 50 accumulated packets, it's probably a smurf attack
if (packet.Type.ToString().Equals("0") &&
packet.Code.ToString().Equals("0") &&
isLocalIP(packet.SourceIP) &&
(packet.PacketTime.Millisecond - ICMPprevious_packet.PacketTime.Millisecond) <= data.dos_threshold &&
ipcache[packet.SourceIP] > 50)
{
pmr = PacketMainReturnType.Drop | PacketMainReturnType.Log | PacketMainReturnType.Popup;
le = new LogEvent(String.Format(multistring.GetString("Smurf Log"), packet.SourceIP.ToString()), this);
le.PMR = PacketMainReturnType.Drop | PacketMainReturnType.Log | PacketMainReturnType.Popup;
LogCenter.Instance.LogEvent(le);
data.BlockCache.Add(packet.SourceIP, new BlockedIP(packet.SourceIP, DateTime.UtcNow, "Smurf Attempt"));
return pmr;
}
ICMPprevious_packet = packet;
}
}
return PacketMainReturnType.Allow;
}
public override PacketMainReturnType interiorMain(ref Packet in_packet)
{
if (in_packet.GetHighestLayer() == Protocol.ARP)
{
ARPPacket arpp = (ARPPacket)in_packet;
if (arpp.isRequest && arpp.Outbound)
{
IPAddr ip = new IPAddr(arpp.ATargetIP.GetAddressBytes());
if (!requestedIPs.Contains(ip))
requestedIPs.Add(ip);
}
else if (!arpp.Outbound)
{
IPAddr ip = new IPAddr(arpp.ASenderIP.GetAddressBytes());
if (!arpp.isRequest)
{
if (requestedIPs.Contains(ip))
{
lock (padlock)
{
if (data.arpCache.ContainsKey(new IPAddr(arpp.ASenderIP.GetAddressBytes())))
{
if (!Utility.ByteArrayEq(data.arpCache[new IPAddr(arpp.ASenderIP.GetAddressBytes())].AddressBytes, arpp.ASenderMac))
{
PacketMainReturnType pmr = 0;
if (data.RectifyAttacks)
pmr = PacketMainReturnType.Edited;
else
pmr = PacketMainReturnType.Drop;
if (data.LogAttacks)
{
LogEvent le = new LogEvent(String.Format(multistring.GetString("Response does not equal cache"), new PhysicalAddress(arpp.ASenderMac).ToString(), arpp.ASenderIP.ToString()), this);
le.PMR = PacketMainReturnType.Log | PacketMainReturnType.Popup;
LogCenter.Instance.LogEvent(le);
}
if (data.RectifyAttacks)
{
arpp.ATargetIP = arpp.ASenderIP;
arpp.ATargetMac = data.arpCache[new IPAddr(arpp.ATargetIP.GetAddressBytes())].AddressBytes;
arpp.ASenderMac = this.Adapter.GetAdapterInformation().InterfaceInformation.GetPhysicalAddress().GetAddressBytes();
arpp.FromMac = arpp.ASenderMac;
arpp.ToMac = arpp.ATargetMac;
arpp.ASenderIP = Adapter.GetAdapterInformation().IPv4;
arpp.Outbound = true;
in_packet = arpp;
}
return pmr;
}
else
{
requestedIPs.Remove(ip);
}
}
else
{
data.arpCache[new IPAddr(arpp.ASenderIP.GetAddressBytes())] = new MACAddr(arpp.ASenderMac);
if (UpdatedArpCache != null)
UpdatedArpCache();
requestedIPs.Remove(ip);
}
}
}
else
{
lock (padlock)
{
if (data.arpCache.ContainsKey(new IPAddr(arpp.ASenderIP.GetAddressBytes())))
{
if (!Utility.ByteArrayEq(data.arpCache[new IPAddr(arpp.ASenderIP.GetAddressBytes())].AddressBytes, arpp.ASenderMac))
{
PacketMainReturnType pmra = 0;
if (data.RectifyAttacks)
pmra = PacketMainReturnType.Edited;
else
pmra = PacketMainReturnType.Drop;
if (data.LogAttacks)
{
LogEvent le = new LogEvent(String.Format(multistring.GetString("Response does not equal cache"), new PhysicalAddress(arpp.ASenderMac).ToString(), arpp.ASenderIP.ToString()), this);
le.PMR = PacketMainReturnType.Log | PacketMainReturnType.Popup;
LogCenter.Instance.LogEvent(le);
}
if (data.RectifyAttacks)
{
arpp.ATargetIP = arpp.ASenderIP;
arpp.ATargetMac = data.arpCache[new IPAddr(arpp.ATargetIP.GetAddressBytes())].AddressBytes;
arpp.ASenderMac = this.Adapter.GetAdapterInformation().InterfaceInformation.GetPhysicalAddress().GetAddressBytes();
arpp.FromMac = arpp.ASenderMac;
arpp.ToMac = arpp.ATargetMac;
arpp.ASenderIP = Adapter.GetAdapterInformation().IPv4;
arpp.Outbound = true;
in_packet = arpp;
}
return pmra;
}
}
}
PacketMainReturnType pmr = 0;
pmr = PacketMainReturnType.Drop;
if (data.LogUnsolic)
{
LogEvent le2 = new LogEvent(String.Format(multistring.GetString("Unsolicited"), new PhysicalAddress(arpp.ASenderMac).ToString(), arpp.ASenderIP.ToString()), this);
le2.PMR = PacketMainReturnType.Log;
}
return pmr;
}
}
else
{
lock (padlock)
{
if (data.arpCache.ContainsKey(new IPAddr(arpp.ASenderIP.GetAddressBytes())))
{
if (!Utility.ByteArrayEq(data.arpCache[new IPAddr(arpp.ASenderIP.GetAddressBytes())].AddressBytes, arpp.ASenderMac))
{
PacketMainReturnType pmr = PacketMainReturnType.Drop;
if (data.LogAttacks)
{
LogEvent le = new LogEvent(String.Format(multistring.GetString("Response does not equal cache"), new PhysicalAddress(arpp.ASenderMac).ToString(), arpp.ASenderIP.ToString()), this);
le.PMR = PacketMainReturnType.Log | PacketMainReturnType.Popup;
LogCenter.Instance.LogEvent(le);
}
return pmr;
}
}
}
}
return 0;
}
return 0;
}
return 0;
}