#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>
#include "SSD1306Ascii.h" // not a default arduino library Used the SSD1306ASCII Libraries instead of adafruit to stop the warning of memory exceeds 
#include "SSD1306AsciiAvrI2c.h" //not a default arduino library https://github.com/greiman/SSD1306Ascii 
 
 
 
byte mac[] = { 0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02 };
 
IPAddress ip (192, 168, 1, 177);
IPAddress gateway (192, 168, 1, 1);
IPAddress subnet (255, 255, 255, 0);
 
EthernetServer server (23);
boolean alreadyConnected = false;
String fakeuser = "";
String telnetinput = "";
String password = "";
byte x = 1;
unsigned short attempts;
File logFile;
bool dhcpstatus;
 
// for use of OLED display can be removed or commented out with no issue
#define I2C_ADDRESS 0x3C //I2C address can change depending on screen
SSD1306AsciiAvrI2c oled;
// end of OLED defines
 
//int LEDPIN = 3;
 
void setup()
{
  Serial.begin (9600);
    if(Ethernet.begin(mac) == 0) {
     // Serial.println("Did not get DHCP address instead using defined IP settings");
      Ethernet.begin (mac, ip, gateway, subnet);
      dhcpstatus = false;
    } else {
     // Serial.println("Using DHCP IP address");
      dhcpstatus = true;
    }
  Serial.print ("current IP address: ");
  Serial.println (Ethernet.localIP ());
  if (!SD.begin(4)) {
   //  Serial.println("SD card intialization failed!");
     return;
  }
  //Serial.println("SD card initialized properly");
    //commented out to get memory to useable state without warnings
  // logFile = SD.open("attack.log", FILE_WRITE); // FAT 16 remember file name max '8+3
  // if (logFile) {
    // logFile.println("booted");
    // logFile.close();
    // Serial.println("file opened, then closed assuming working");
  // } else {
    // Serial.println("SD card error");
  //}
 
  oled.begin(&Adafruit128x64, I2C_ADDRESS);
  oled.setFont(Adafruit5x7); 
  uint32_t m = micros();
  oled.clear();
//notification led blink
 
//pinMode(LEDPIN, OUTPUT); //don't use pin 13  the default led on Arduino as it is used by the SD card on the ethernet shield
//digitalWrite(LEDPIN, LOW); Serial.println("LED OFF to start");
}
 
void loop() {
  EthernetClient client = server.available ();
  if (client) {
      if (!alreadyConnected) {
                    client.flush();
                    Serial.println("telnet connected");
	                  server.println("telnet connected");
	                  server.print ("user: ");
                    alreadyConnected = true;
      }
        while (client.available()){              
	                  char newChar = client.read();
	                  if (newChar == 0x0D){	//newline? could be '\n' username completed yet?
                      if(x == 1) {
                        fakeuser = telnetinput;
                        telnetinput = "";
                        ++x;
                      } else  {
                        password = telnetinput;
                        telnetinput = "";
                        ++x;
                      }
                      if ( x <= 2) {
                      //  digitalWrite(3, HIGH); //light up led for notification
                      //  Serial.print("User:");
                      //  Serial.print(fakeuser);
                      //  Serial.println(" has started an attempt to login");
                      }
                      if ( x > 2) {   
                      //   digitalWrite(LEDPIN, HIGH); //light up led for notification
                         Serial.print("user:");
                         Serial.print(fakeuser);
                         Serial.print(":password:");
                         Serial.print(password);
                         //Serial.print("    counter: "); //debugging
                         //Serial.println(x); //debugging
                         ++attempts;
                         Serial.print(":attempt#:");
                         Serial.println(attempts);
 
                        //oled display of current attempt comment out if not needed
 
 
                          oled.clear();  
                          oled.print("IP:");
                          oled.println(Ethernet.localIP ());
                          oled.print("Using DHCP: ");
                          oled.print(dhcpstatus ? "Yes" : "No");
                          oled.println("");
                          oled.println("User:");
                          oled.println(fakeuser);
                          oled.println("Password:");
                          oled.println(password);
                          oled.print("attempt#: ");
                          oled.println(attempts); 
                       //end of oled display to be commented out
 
 
 
                         logFile = SD.open("attack.log", FILE_WRITE); // FAT 16 remember file name max '8+3
                         if (logFile) {
                              logFile.print("user:");
                              logFile.print(fakeuser);
                              logFile.print(":Password:");
                              logFile.print(password);
                              logFile.print(":attempt#:");
                              logFile.println(attempts);
                              logFile.close();
                              Serial.println("Attempt logged to file");
 
                         } else {
                              Serial.println("SD card error attempt not logged");
 
                         }   
                      }
                      if (x == 5) { // after 3rd password failure disconnect current attack and reset things to zero
                       client.stop();
                       alreadyConnected = false;
                       fakeuser = "";
                       telnetinput = "";
                       password = "";                         
                       x = 1;
                       //digitalWrite(3, LOW); Serial.println("LED OFF");//turn off LED for next try
                      }
                      client.flush();
 
                      delay(2000); // give a delay make the attacker think they are authenticating against something
 
                      oled.clear(); // turn off oled
 
                     server.print("password:");
                    // digitalWrite(3, LOW); Serial.println("LED OFF"); //turn off LED for next try
	                  } else {
                         if(isPrintable(newChar)){ //clean up output likes to put newlines for passwords and lots of junk on intial login
                              if(x == 1) { //first attempt will be the login lets just capture alphanumberics
                                   if(isAlphaNumeric(newChar)){
                                        telnetinput += newChar;
                                   }
                              } else {
	                                telnetinput += newChar;	//add adiditional character to the user trying to authenticate untill newline is entered
                                  client.flush();
                              }
                         }
	                  }
          }
    }
}