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README.md

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+# Fake Telnet
+
+Simple socket server which shows a rickroll on connect, made for a school honeypot

impTel.cpp

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+#include <iostream>
+#include <cstring>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <map>
+#include <chrono>
+#include <thread>
+#include <csignal>
+#include <fstream>  
+#include <sstream>  
+#include <sqlite3.h>
+
+
+void clearClient(int client_socket){
+  const char* clearCmd = "\033c";
+  send(client_socket, clearCmd, strlen(clearCmd), 0);
+}
+
+void handleSIGPIPE(int) {
+    std::cerr << "Received SIGPIPE signal" << std::endl;
+}
+
+void setSignalHandlers() {
+    signal(SIGPIPE, handleSIGPIPE);
+}
+
+void sendTelnetOption(int client_socket, unsigned char option, unsigned char suboption) {
+    unsigned char buffer[3];
+    buffer[0] = 0xFF;  
+    buffer[1] = option;
+    buffer[2] = suboption;
+    int bytes_sent = send(client_socket, buffer, 3, 0);
+    if (bytes_sent == -1) {
+        perror("Failed to send telnet option");
+    }
+}
+
+void sendBusyBoxBanner(int client_socket) {
+    sendTelnetOption(client_socket, 0xFD, 0x18);
+    sendTelnetOption(client_socket, 0xFD, 0x1F);
+    sendTelnetOption(client_socket, 0xFB, 0x03);
+    sendTelnetOption(client_socket, 0xFE, 0x01);
+
+    const char* banner = "BusyBox (built-in shell)\r\n";
+    int bytes_sent = send(client_socket, banner, strlen(banner), 0);
+    if (bytes_sent == -1) {
+        perror("Failed to send banner");
+    }
+}
+
+void sendFrames(int client_socket) {
+    std::ifstream framesFile("frames.txt");
+    std::string frame;
+    std::string delimiter = "fStart";
+    std::ostringstream currentFrame;
+    while (std::getline(framesFile, frame)) {
+        if (frame == delimiter) {
+            std::string frameToSend = currentFrame.str();
+            int bytes_sent = send(client_socket, frameToSend.c_str(), frameToSend.size(), 0);
+            if (bytes_sent == -1) {
+                perror("Failed to send frame");
+                break;
+            }
+
+            currentFrame.str("");
+            std::this_thread::sleep_for(std::chrono::milliseconds(42));
+	    clearClient(client_socket);
+        } else {
+            currentFrame << frame << "\r\n";
+        }
+    }
+}
+
+void initializeDatabase() {
+    sqlite3 *db;
+    int rc = sqlite3_open("connections.db", &db);
+    if (rc) {
+        std::cerr << "Can't open database: " << sqlite3_errmsg(db) << std::endl;
+        sqlite3_close(db);
+        return;
+    }
+
+    const char* createTableSQL = "CREATE TABLE IF NOT EXISTS connections (ip TEXT PRIMARY KEY, count INT);";
+    rc = sqlite3_exec(db, createTableSQL, 0, 0, 0);
+    if (rc != SQLITE_OK) {
+        std::cerr << "SQL error: " << sqlite3_errmsg(db) << std::endl;
+        sqlite3_close(db);
+        return;
+    }
+
+    sqlite3_close(db);
+}
+
+
+void updateConnectionCount(const std::string& ip) {
+    sqlite3* db;
+    int rc = sqlite3_open("connections.db", &db);
+    if (rc) {
+        std::cerr << "Can't open database: " << sqlite3_errmsg(db) << std::endl;
+        sqlite3_close(db);
+        return;
+    }
+
+    const char* insertSQL = "INSERT OR REPLACE INTO connections (ip, count) VALUES (?, COALESCE((SELECT count FROM connections WHERE ip = ?), 0) + 1);";
+    sqlite3_stmt* stmt;
+    rc = sqlite3_prepare_v2(db, insertSQL, -1, &stmt, 0);
+    if (rc != SQLITE_OK) {
+        std::cerr << "SQL error: " << sqlite3_errmsg(db) << std::endl;
+        sqlite3_close(db);
+        return;
+    }
+
+    rc = sqlite3_bind_text(stmt, 1, ip.c_str(), -1, SQLITE_STATIC);
+    rc = sqlite3_bind_text(stmt, 2, ip.c_str(), -1, SQLITE_STATIC);
+    rc = sqlite3_step(stmt);
+    sqlite3_finalize(stmt);
+
+    sqlite3_close(db);
+}
+
+void ftel() {
+    int server_socket = socket(AF_INET, SOCK_STREAM, 0);
+    initializeDatabase();
+    if (server_socket == -1) {
+        perror("Socket creation error");
+        return;
+    }
+
+    sockaddr_in server_address;
+    server_address.sin_family = AF_INET;
+    server_address.sin_addr.s_addr = INADDR_ANY;
+    server_address.sin_port = htons(23);
+
+    if (bind(server_socket, (struct sockaddr*)&server_address, sizeof(server_address)) == -1) {
+        perror("Binding error");
+        return;
+    }
+
+    if (listen(server_socket, 1) == -1) {
+        perror("Listening error");
+        return;
+    }
+
+    std::cout << "Waiting for a connection..." << std::endl;
+
+    while (true) {
+        sockaddr_in client_address;
+        socklen_t client_address_len = sizeof(client_address);
+        int client_socket = accept(server_socket, (struct sockaddr*)&client_address, &client_address_len);
+
+        if (client_socket == -1) {
+            perror("Accepting error");
+            continue;
+        }
+
+        std::string connectedClient = inet_ntoa(client_address.sin_addr);
+
+        std::cout << "Connection established with: " << connectedClient << std::endl;
+
+        sendBusyBoxBanner(client_socket);
+
+        sendFrames(client_socket);
+
+        close(client_socket);
+        std::cout << "Message sent and connection closed." << std::endl;
+
+	updateConnectionCount(connectedClient);
+    }
+
+    close(server_socket);
+}
+
+int main() {
+    setSignalHandlers();
+    ftel();
+    return 0;
+}