hide_openssh_banner.py

import socket, subprocess, random, string

def generate_random_string(length=10):
    characters = string.ascii_uppercase + string.digits
    return ''.join(random.choice(characters) for _ in range(length))

def grab_ssh_banner(port=22, timeout=5):
    host = 'localhost'
    try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.settimeout(timeout)
        sock.connect((host, port))
        
        banner = sock.recv(1024).decode('utf-8').strip()
        sock.close()
        return banner.strip()
    except ConnectionRefusedError:
        print("FAILED")
    except socket.timeout:
        print("FAILED")
    except Exception as e:
        print(f"FAILED")
    exit(1)

def run_command(command):
    try:
        result = subprocess.run(command,  shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        return result.stdout.decode().strip()
    except subprocess.CalledProcessError as e:
        print(e)
        print("FAILED")
    exit(1)

print("""
    OpenSSH Banner Hidder
    =====================
""")
port = int(input("Enter Port: "))
print("[+] Getting Current Banner...", end='')
banner = grab_ssh_banner(port)
print('DONE')

pts = banner.split("-")
banner = "-".join(pts[2:])
len_banner = len(banner)
new_banner = generate_random_string(len_banner)

print("Current Banner:", banner)
print("New Banner:", new_banner)

print('[+] Copying Binary from /usr/sbin/sshd...')
run_command("cp /usr/sbin/sshd ./sshd")

print('[+] Searching for Current Banner...', end='')
out = run_command(f"strings -t d -a -n {len_banner} sshd | grep -i \"{banner}\"")
if len(out) == 0 or len(out.strip().split(" ")) < 2:
    print("NOT FOUND")
    exit(1)
print('FOUND')

offset = int(out.split(" ")[0])
print ("[+] Overwriting New Banner...", end='')
with open('sshd', 'r+b') as fp:
    fp.seek(offset)
    fp.write(new_banner.encode())

out = run_command(f"strings -t d -a -n {len_banner} sshd | grep -i \"{new_banner}\"")
if len(out) == 0 or len(out.strip().split(" ")) < 2:
    print("FAILED")
    exit(1)

if out.split(" ")[1].strip() != new_banner:
    print("FAILED")
    exit(1)
print('DONE')

print("[+] Stopping OpenSSH Server...", end='')
run_command("sudo systemctl stop ssh ssh.socket")
print('DONE')

print("[+] Copying binary to /usr/sbin/sshd...", end='')
run_command("sudo cp /usr/sbin/sshd ./sshd.back")
run_command("sudo cp ./sshd /usr/sbin/sshd")
print('DONE')

print("[+] Starting OpenSSH Server...", end='')
run_command("sudo systemctl start ssh ssh.socket")
print('DONE')

print("[+] Cleaning Up...", end='')
run_command("rm ./sshd")
print('DONE')

print("[+] Checking Banner...", end='')
banner2 = grab_ssh_banner()
pts = banner2.split("-")
banner2 = "-".join(pts[2:])
if banner2 == new_banner:
    print('OK')
    print('\n\033[32;1mOpenSSH Banner Hidden Successfully\033[0m\n')
    exit(0)

print("FAILED")
print("[+] Restoring ssh...", end='')
run_command("sudo systemctl stop ssh ssh.socket")
run_command("sudo cp ./sshd.back /usr/sbin/sshd")
run_command("sudo systemctl start ssh ssh.socket")
print('DONE')

print('\n\033[31;1mFailed to Hide OpenSSH Banner\033[0m\n')