You are scanning your victim and discovering some open ports:
80,135,445 etc. This will help you to choose your methodology of future enumeration, right?
With regular NMAP scan, like:
bt6# nmap 1.2.3.4
the target will be scanned, by default, for 1000 well known ports.Stop for a second, and think if all of these ports will be open.
You, as a hacker, will stuck for some time, enumerating fake-open ports. Furthermore, it will be immediately logged in system.
My teacher gave this idea, and implementation with scapy.
The algorithm is simple:
Got SYN packet > Send back SYN-ACK with SEQ+1.
That was fine, but works in half of times. Not a production level.
Also, he told that he wasn't first that invented this method.
I've googled, and not found anything about that.
So, i've asked for help from kernel modules :)
IPTABLES - Port-forwarding.
What we'll need?
1. Server that will respond to every incoming SYN packet.
2. IPTABLES or other firewall
3. IPSET (for use in iptables)
4. Real-time monitoring for adding/removing ports from SET.
You can open all ports, but i don't think it is necessary.
I will open only well-known ports of nmap. Everyone use nmap, don't think so?
First of all, DROP reset (RST) packet in OUTPUT table.
# iptables -A OUTPUT -p tcp -m tcp --tcp-flags RST RST -j DROPWhy? If some port is closed, your system will not respond with RST packet back, and other reasons, like got SYN-ACK, or RST, etc.
Secondly, DROP ICMP packet 'destination unreachable' in OUTPUT table.
# iptables -A OUTPUT -p icmp -m icmp --icmp-type 3 -j DROPWe don't want to allow somebody to know about any closed port in our system.
Create a set in IPSET:
# ipset create set_name bitmap:port range 0-65535
Add your well-known ports to this set:
# ipset add set_name port_number
If you want to test your specific port, if it in the set:
# ipset test set_name 8888 8888 is in set set_name.
Need a well-known port list? take it:
# nmap 127.0.0.1 -dd |grep -E 'syn-ack|no-response'|cut -d'/' -f1 > ports.txtThis will work if you dropped a RESET packet in first step.
Assuming, you know BASH a little, you will know how to code a simple script that will add all ports to set in one click.
Ok. IPSET SET is created, let's make a main IPTABLES rule:
# iptables -t nat -A PREROUTING -p tcp -m set --match-set set_name dst -j REDIRECT --to-ports 8888
You may ask: "What is port 8888?"
That's the point. It is your server script that is listening only on one port, and answering everyone with a connection!
If you don't know how to make a server, you can use 'socat' for example:
# socat TCP-LISTEN:8888,reuseaddr,fork -
Otherwise, you can improve this script for you:
#!/usr/bin/env python
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
host = 'YOUR_IP_ADDRESS'
port = 8888
s.bind((host, port))
s.listen(5)
try:
while True:
c, addr = s.accept()
data = c.recv(2048)
response = ''
c.send("Welcome %s. Logged.\n" % addr[0])
c.close()
except KeyboardInterrupt:
s.close()
It will listen on 8888 port (chose yours), and will send back "Welcome IP_ADDR. Logged."
The output:
# nc 192.168.100.100 8888 Welcome 192.168.200.200. Logged.
Proof of concept: Nmap (fast) scanning
# nmap -F 192.168.100.100 Starting Nmap 6.46 ( http://nmap.org ) at 2014-10-13 03:06 IDT Nmap scan report for 192.168.100.100 Host is up (0.0026s latency). PORT STATE SERVICE 7/tcp open echo 9/tcp open discard 13/tcp open daytime 21/tcp open ftp 22/tcp open ssh 23/tcp open telnet 25/tcp open smtp 26/tcp open rsftp 37/tcp open time 53/tcp open domain 79/tcp open finger 80/tcp open http 81/tcp open hosts2-ns 88/tcp open kerberos-sec 106/tcp open pop3pw 110/tcp open pop3 111/tcp open rpcbind 113/tcp open ident 119/tcp open nntp 135/tcp open msrpc 139/tcp open netbios-ssn 143/tcp open imap 144/tcp open news 179/tcp open bgp 199/tcp open smux 389/tcp open ldap 427/tcp open svrloc 443/tcp open https 444/tcp open snpp 445/tcp open microsoft-ds 465/tcp open smtps 513/tcp open login 514/tcp open shell 515/tcp open printer 543/tcp open klogin 544/tcp open kshell 548/tcp open afp 554/tcp open rtsp 587/tcp open submission 631/tcp open ipp 646/tcp open ldp 873/tcp open rsync 990/tcp open ftps 993/tcp open imaps 995/tcp open pop3s 1025/tcp open NFS-or-IIS 1026/tcp open LSA-or-nterm 1027/tcp open IIS 1028/tcp open unknown 1029/tcp open ms-lsa 1110/tcp open nfsd-status 1433/tcp open ms-sql-s 1720/tcp open H.323/Q.931 1723/tcp open pptp 1755/tcp open wms 1900/tcp open upnp 2000/tcp open cisco-sccp 2001/tcp open dc 2049/tcp open nfs 2121/tcp open ccproxy-ftp 2717/tcp open pn-requester 3000/tcp open ppp 3128/tcp open squid-http 3306/tcp open mysql 3389/tcp open ms-wbt-server 3986/tcp open mapper-ws_ethd 4899/tcp open radmin 5000/tcp open upnp 5009/tcp open airport-admin 5051/tcp open ida-agent 5060/tcp open sip 5101/tcp open admdog 5190/tcp open aol 5357/tcp open wsdapi 5432/tcp open postgresql 5631/tcp open pcanywheredata 5666/tcp open nrpe 5800/tcp open vnc-http 5900/tcp open vnc 6000/tcp open X11 6001/tcp open X11:1 6646/tcp open unknown 7070/tcp open realserver 8000/tcp open http-alt 8008/tcp open http 8009/tcp open ajp13 8080/tcp open http-proxy 8081/tcp open blackice-icecap 8443/tcp open https-alt 8888/tcp open sun-answerbook 9100/tcp open jetdirect 9999/tcp open abyss 10000/tcp open snet-sensor-mgmt 32768/tcp open filenet-tms 49152/tcp open unknown 49153/tcp open unknown 49154/tcp open unknown 49155/tcp open unknown 49156/tcp open unknown 49157/tcp open unknown MAC Address: 00:0C:29:73:95:1C (VMware) Nmap done: 1 IP address (1 host up) scanned in 1.43 seconds
Remains to solve only one problem. What if you want to open a port for some reason? like netcat...
We need a realtime monitoring for listening ports, and if the there appeared one or more new listen ports, we need to remove them from IPSET set. Otherwise if one or more listening ports disappeared, we have to add them to the SET.
A fast and dirty implementation of this:
#!/usr/bin/python
from subprocess import check_output
import re
from time import sleep
set_name = 'rports'
def open_ports():
netstat = check_output('netstat -tan',shell=True)
lports = re.findall(r'(?<=\:)[0-9]{1,5}\w(?=.+listen)',netstat.lower())
lports = list(set(lports))
return lports
tmp_ports = []
while 1:
openports = open_ports()
new_open = list(set(openports) - set(tmp_ports))
new_closed = list(set(tmp_ports) - set(openports))
if len(new_open):
for port in new_open:
#print 'removing port %s from ipset' % port
os.system('ipset del %s %s' % (set_name,port))
if len(new_closed):
for port in new_closed:
#print 'adding port %d to ipset' % int(port)
os.system('ipset add %s %s' % (set_name,port))
tmp_ports = openports
sleep(1)
This will run 'netstat -tan' and look for changes in LISTEN ports.Code on github: https://github.com/nopernik/open-ports-honeypot
Credits:
The idea - by Gil Rozenberg
Implementation with iptables/ipset - by Alexander Korznikov
nice to be a root#
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