smtp_timing.py

import socket
import time
import statistics

# SMTP server
SMTP_SERVER = 'mail.server.com'
SMTP_PORT = 25

# Lists of valid and invalid email addresses (without domain)
valid_users = [
    'info',
    'sales',
    'contact'
    'joe',
    'dave'
]

invalid_users = [
    'ksdfkjasjfk',
    'flforkmdkd',
    'lkapwoekropkf',
    'lkso',
    'lkasdflkjas',
    'ksjfljalf',
    'kjfoiewjfsdjf',
    'lokjfopwkfsadk',
    'skljfklasdjfkl',
    'skfdjlksdjflsj'
]

# Domain(s)
domains = ['server.com']

# Number of tests per email address
TEST_COUNT = 10

# Tolerance for timing differences (in seconds)
TIMING_THRESHOLD = 0.1

# Function to send commands and capture the response time
def send_smtp_command(sock, command):
    sock.send(command.encode())
    return sock.recv(1024).decode()

# Measuring the average response times for valid addresses
valid_avg_times = []
for domain in domains:
    for user in valid_users:
        email = f'{user}@{domain}'
        times = []
        responses = []  # List to store all server responses
        status_codes = []  # List to store all status codes
        print(f"Measuring response times for {email} (valid address)...")
        for i in range(TEST_COUNT):
            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            sock.connect((SMTP_SERVER, SMTP_PORT))
            
            send_smtp_command(sock, 'HELO fingonlab.tech\r\n')
            send_smtp_command(sock, 'MAIL FROM:<test@fingonlab.tech>\r\n')
            
            start_time = time.time()
            response = send_smtp_command(sock, f'RCPT TO:<{email}>\r\n')
            end_time = time.time()
            
            times.append(end_time - start_time)
            responses.append(response)  
            
            # Extracting the status code
            status_code = int(response.split()[0])
            status_codes.append(status_code)
            
            send_smtp_command(sock, 'QUIT\r\n')
            sock.close()
            time.sleep(1)
        
        # Calculate the average time for this address
        valid_avg_times.append(statistics.mean(times))

        print(f"Server responses for {email}:")
        for response, status_code in zip(responses, status_codes):
            if status_code > 299:
                print(f"\033[91mResponse: {response.strip()}, Status Code: {status_code}\033[0m")
            else:
                print(f"Response: {response.strip()}, Status Code: {status_code}")

# Measuring the average response times for invalid addresses
invalid_avg_times = []
for domain in domains:
    for user in invalid_users:
        email = f'{user}@{domain}'
        times = []
        responses = []  # List to store all server responses
        status_codes = []  # List to store all status codes
        print(f"Measuring response times for {email} (invalid address)...")
        for i in range(TEST_COUNT):
            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            sock.connect((SMTP_SERVER, SMTP_PORT))
            
            send_smtp_command(sock, 'HELO fingonlab.tech\r\n')
            send_smtp_command(sock, 'MAIL FROM:<test@fingonlab.tech>\r\n')
            
            start_time = time.time()
            response = send_smtp_command(sock, f'RCPT TO:<{email}>\r\n')
            end_time = time.time()
            
            times.append(end_time - start_time)
            responses.append(response)  # Storing server response
            
            # Extracting the status code
            status_code = int(response.split()[0])
            status_codes.append(status_code)
            
            send_smtp_command(sock, 'QUIT\r\n')
            sock.close()
            time.sleep(1)
        
        # Calculate the average time for this address
        invalid_avg_times.append(statistics.mean(times))

        # Display server responses and status codes
        print(f"Server responses for {email}:")
        for response, status_code in zip(responses, status_codes):
            print(f"Response: {response.strip()}, Status Code: {status_code}")

# Calculate the overall averages for valid and invalid email addresses
mean_valid = statistics.mean(valid_avg_times)
mean_invalid = statistics.mean(invalid_avg_times)

# Display results
print("\nResults:")
print(f"Overall average time for valid addresses: {mean_valid:.4f} seconds")
print(f"Overall average time for invalid addresses: {mean_invalid:.4f} seconds")

# Check for timing attack indication
if abs(mean_valid - mean_invalid) > TIMING_THRESHOLD:
    print(f"Possible timing attack detected! Difference: {abs(mean_valid - mean_invalid):.4f} seconds")
else:
    print("No timing attack detected.")