dcrouter/test/suite/security/test.ip-reputation.ts

import { tap, expect } from '@git.zone/tstest/tapbundle';
import * as plugins from '../plugins.js';
import * as net from 'net';
import { startTestServer, stopTestServer, TEST_PORT, sendEmailWithRawSocket } from '../server.loader.js';
import type { SmtpServer } from '../../../ts/mail/delivery/smtpserver/index.js';

let testServer: SmtpServer;

tap.test('setup - start test server', async () => {
  testServer = await startTestServer();
  await plugins.smartdelay.delayFor(1000);
});

tap.test('IP Reputation - Suspicious hostname in EHLO', async (tools) => {
  const done = tools.defer();
  
  const socket = net.createConnection({
    host: 'localhost',
    port: TEST_PORT,
    timeout: 30000
  });
  
  let dataBuffer = '';
  
  socket.on('data', (data) => {
    dataBuffer += data.toString();
    console.log('Server response:', data.toString());
    
    if (dataBuffer.includes('220 ')) {
      // Use suspicious hostname
      socket.write('EHLO suspicious-host.badreputation.com\r\n');
      dataBuffer = '';
    } else if (dataBuffer.includes('250') || dataBuffer.includes('550') || dataBuffer.includes('521')) {
      const accepted = dataBuffer.includes('250');
      const rejected = dataBuffer.includes('550') || dataBuffer.includes('521');
      
      console.log(`Suspicious hostname: accepted=${accepted}, rejected=${rejected}`);
      expect(accepted || rejected).toBeTrue();
      
      if (rejected) {
        console.log('IP reputation check working - suspicious host rejected at EHLO');
      }
      
      socket.write('QUIT\r\n');
      socket.end();
      done.resolve();
    }
  });
  
  socket.on('error', (err) => {
    console.error('Socket error:', err);
    done.reject(err);
  });
  
  await done.promise;
});

tap.test('IP Reputation - Blacklisted sender domain', async (tools) => {
  const done = tools.defer();
  
  const socket = net.createConnection({
    host: 'localhost',
    port: TEST_PORT,
    timeout: 30000
  });
  
  let dataBuffer = '';
  let step = 'greeting';
  
  socket.on('data', (data) => {
    dataBuffer += data.toString();
    console.log('Server response:', data.toString());
    
    if (step === 'greeting' && dataBuffer.includes('220 ')) {
      step = 'ehlo';
      socket.write('EHLO testclient\r\n');
      dataBuffer = '';
    } else if (step === 'ehlo' && dataBuffer.includes('250')) {
      step = 'mail';
      // Use known spam/blacklisted domain
      socket.write('MAIL FROM:<spam@blacklisted.com>\r\n');
      dataBuffer = '';
    } else if (step === 'mail') {
      if (dataBuffer.includes('250')) {
        console.log('Blacklisted sender accepted at MAIL FROM');
        step = 'rcpt';
        socket.write('RCPT TO:<recipient@example.com>\r\n');
        dataBuffer = '';
      } else if (dataBuffer.includes('550') || dataBuffer.includes('553')) {
        console.log('Blacklisted sender rejected - IP reputation check working');
        expect(true).toBeTrue();
        
        socket.write('QUIT\r\n');
        socket.end();
        done.resolve();
      }
    } else if (step === 'rcpt') {
      const accepted = dataBuffer.includes('250');
      const rejected = dataBuffer.includes('550') || dataBuffer.includes('553');
      
      console.log(`Blacklisted domain at RCPT: accepted=${accepted}, rejected=${rejected}`);
      expect(accepted || rejected).toBeTrue();
      
      socket.write('QUIT\r\n');
      socket.end();
      done.resolve();
    }
  });
  
  socket.on('error', (err) => {
    console.error('Socket error:', err);
    done.reject(err);
  });
  
  await done.promise;
});

tap.test('IP Reputation - Known good sender', async (tools) => {
  const done = tools.defer();
  
  const socket = net.createConnection({
    host: 'localhost',
    port: TEST_PORT,
    timeout: 30000
  });
  
  let dataBuffer = '';
  let step = 'greeting';
  
  socket.on('data', (data) => {
    dataBuffer += data.toString();
    console.log('Server response:', data.toString());
    
    if (step === 'greeting' && dataBuffer.includes('220 ')) {
      step = 'ehlo';
      socket.write('EHLO localhost\r\n');
      dataBuffer = '';
    } else if (step === 'ehlo' && dataBuffer.includes('250')) {
      step = 'mail';
      // Use legitimate sender
      socket.write('MAIL FROM:<test@localhost>\r\n');
      dataBuffer = '';
    } else if (step === 'mail' && dataBuffer.includes('250')) {
      step = 'rcpt';
      socket.write('RCPT TO:<recipient@example.com>\r\n');
      dataBuffer = '';
    } else if (step === 'rcpt' && dataBuffer.includes('250')) {
      console.log('Good sender accepted - IP reputation allows legitimate senders');
      expect(true).toBeTrue();
      
      socket.write('QUIT\r\n');
      socket.end();
      done.resolve();
    }
  });
  
  socket.on('error', (err) => {
    console.error('Socket error:', err);
    done.reject(err);
  });
  
  await done.promise;
});

tap.test('IP Reputation - Multiple connections from same IP', async (tools) => {
  const done = tools.defer();
  const connections: net.Socket[] = [];
  let completedConnections = 0;
  const totalConnections = 3;
  
  // Create multiple connections rapidly
  for (let i = 0; i < totalConnections; i++) {
    const socket = net.createConnection({
      host: 'localhost',
      port: TEST_PORT,
      timeout: 30000
    });
    
    connections.push(socket);
    
    socket.on('data', (data) => {
      const response = data.toString();
      console.log(`Connection ${i + 1} response:`, response);
      
      if (response.includes('220')) {
        socket.write('EHLO testclient\r\n');
      } else if (response.includes('250')) {
        socket.write('QUIT\r\n');
        socket.end();
      } else if (response.includes('421') || response.includes('550')) {
        // Connection rejected due to rate limiting or reputation
        console.log(`Connection ${i + 1} rejected - IP reputation/rate limiting active`);
        socket.end();
      }
    });
    
    socket.on('close', () => {
      completedConnections++;
      if (completedConnections === totalConnections) {
        console.log('All connections completed');
        expect(true).toBeTrue();
        done.resolve();
      }
    });
    
    socket.on('error', (err) => {
      console.error(`Connection ${i + 1} error:`, err.message);
      completedConnections++;
      if (completedConnections === totalConnections) {
        done.resolve();
      }
    });
    
    // Small delay between connections
    if (i < totalConnections - 1) {
      await plugins.smartdelay.delayFor(100);
    }
  }
  
  await done.promise;
});

tap.test('IP Reputation - Suspicious patterns in email', async (tools) => {
  const done = tools.defer();
  
  const socket = net.createConnection({
    host: 'localhost',
    port: TEST_PORT,
    timeout: 30000
  });
  
  let dataBuffer = '';
  let step = 'greeting';
  
  socket.on('data', (data) => {
    dataBuffer += data.toString();
    console.log('Server response:', data.toString());
    
    if (step === 'greeting' && dataBuffer.includes('220 ')) {
      step = 'ehlo';
      socket.write('EHLO testclient\r\n');
      dataBuffer = '';
    } else if (step === 'ehlo' && dataBuffer.includes('250')) {
      step = 'mail';
      socket.write('MAIL FROM:<sender@example.com>\r\n');
      dataBuffer = '';
    } else if (step === 'mail' && dataBuffer.includes('250')) {
      step = 'rcpt';
      // Multiple recipients (spam pattern)
      socket.write('RCPT TO:<recipient1@example.com>\r\n');
      dataBuffer = '';
    } else if (step === 'rcpt' && dataBuffer.includes('250')) {
      step = 'rcpt2';
      socket.write('RCPT TO:<recipient2@example.com>\r\n');
      dataBuffer = '';
    } else if (step === 'rcpt2' && dataBuffer.includes('250')) {
      step = 'rcpt3';
      socket.write('RCPT TO:<recipient3@example.com>\r\n');
      dataBuffer = '';
    } else if (step === 'rcpt3') {
      if (dataBuffer.includes('250')) {
        step = 'data';
        socket.write('DATA\r\n');
        dataBuffer = '';
      } else if (dataBuffer.includes('452') || dataBuffer.includes('550')) {
        console.log('Multiple recipients limited - reputation control active');
        expect(true).toBeTrue();
        
        socket.write('QUIT\r\n');
        socket.end();
        done.resolve();
      }
    } else if (step === 'data' && dataBuffer.includes('354')) {
      // Email with spam-like content
      const email = [
        `From: sender@example.com`,
        `To: recipient1@example.com, recipient2@example.com, recipient3@example.com`,
        `Subject: URGENT!!! You've won $1,000,000!!!`,
        `Date: ${new Date().toUTCString()}`,
        `Message-ID: <spam-pattern-${Date.now()}@example.com>`,
        '',
        'CLICK HERE NOW!!! Limited time offer!!!',
        'Visit http://suspicious-link.com/win-money',
        'Act NOW before it\'s too late!!!',
        '.',
        ''
      ].join('\r\n');
      
      socket.write(email);
      dataBuffer = '';
    } else if (dataBuffer.includes('250 ') || dataBuffer.includes('550 ')) {
      const result = dataBuffer.includes('250') ? 'accepted' : 'rejected';
      console.log(`Suspicious content email ${result}`);
      expect(true).toBeTrue();
      
      socket.write('QUIT\r\n');
      socket.end();
      done.resolve();
    }
  });
  
  socket.on('error', (err) => {
    console.error('Socket error:', err);
    done.reject(err);
  });
  
  await done.promise;
});

tap.test('cleanup - stop test server', async () => {
  await stopTestServer(testServer);
});

tap.start();