gists/dictionary_attack/attack.py
2018-10-11 16:45:30 +02:00

82 lines
1.9 KiB
Python

# dead simple dictionary attack for fixed-length passwords.
# this is far from optimal.
from collections import defaultdict
import argparse
import sys
import random
program = sys.argv[0]
args = sys.argv[1:]
parser = argparse.ArgumentParser(
description="attack: produce fixed-length strings from dictionaries")
parser.add_argument(
'length', type=int,
help="the length of the strings to output")
parser.add_argument(
'path', metavar='text-file', nargs='+',
help="a dictionary file containing one string per line")
parser.add_argument(
'-n', metavar='limit', type=float, default='inf',
help="output this many strings and exit")
parser.add_argument(
'-s', metavar='seed', type=int, default=None,
help="use as a seed for the random number generator")
a = parser.parse_args(args)
seed = a.s
limit = a.n
paths = a.path
fixed_length = a.length
del a
lines = []
for path in paths:
with open(path, "r") as f:
for line in f:
lines.append(line.strip('\r\n'))
nlines = defaultdict(lambda: [])
ncount = defaultdict(lambda: 0)
for line in lines:
length = len(line)
if length == 0 or length > fixed_length:
continue
nlines[length].append(line)
ncount[length] += 1
del lines
if seed is not None:
random.seed(seed)
lengths = list(ncount.keys())
length_weights = list(ncount.values())
i = 0
while i < limit:
s = ''
new_weights = length_weights.copy()
while len(s) < fixed_length:
if len(s) > 0:
for j, length in enumerate(lengths):
if len(s) + length > fixed_length:
new_weights[j] = 0
if sum(new_weights) == 0:
s = ''
new_weights = length_weights.copy()
continue
chosen_length = random.choices(lengths, new_weights)[0]
s += random.choice(nlines[chosen_length])
try:
print(s)
except OSError:
# pipe closed.
break
i += 1