RSA password bruteforce

rsa-brute.py

#!/usr/bin/env python3
import paramiko
from paramiko import rsakey

kf = open("/root/.ssh/old/id_rsa", "r")

prefix = "prefix"
chars = {"a", "b", "c"}


def passgen(prefix, chars):
    if not chars:
        return

    # TODO: re-implement using an iterative approach to improve performance
    for c in chars:
        newp = ''.join([prefix, c])
        yield newp
        yield from passgen(newp, chars - {c})


for d in passgen(prefix, chars):
    kf.seek(0)
    try:
        nk = rsakey.RSAKey.from_private_key(kf, password=d)
        print("success", d)
        break
    except paramiko.ssh_exception.SSHException:
        print("fail", d)