> For the complete documentation index, see [llms.txt](https://www.hackbook.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.hackbook.io/reconnaissance/active-scanning.md).

# Active Scanning

## Live Host Scanning

Commonly done with ICMP sweeps (typically disallowed by firewalls and secure and windows 10+). We listen for echo replies and know the host is alive if it responds(fping, hping, nmap, nc): 

* <mark style="color:green;">fping -a -g</mark>  //<mark style="color:yellow;">-a</mark> alive scan, <mark style="color:yellow;">-g</mark> generate list&#x20;
* <mark style="color:green;">nmap -sn</mark>  //<mark style="color:yellow;">-sn</mark> "ping sweep" but its <mark style="color:yellow;">actually an arp sweep</mark>&#x20;
* <mark style="color:green;">nmap -sn --disable-arp-ping</mark> //makes it a real ping sweep

### ARP Discovery Scan

ARP Discovery scan for live hosts. Just finds the hosts, not a port scan!\
\
**netdiscover:**\ <mark style="color:green;">`netdiscover -i tap0 -r 10.10.10.0/24`</mark>\
`or`\ <mark style="color:green;">`netdiscover -i tap0 -S -L -f -r 10.10.10.0/24`</mark>\
\
a**rp-scan:**\ <mark style="color:green;">`arp-scan -I tap0 10.10.10.0/24`</mark>

**hping:**\
This tool lets us craft our packets to run the scans we want **without extra noise**.\ <mark style="color:green;">`hping3 -S <ip> -p 80 -c 2`</mark> \ <mark style="color:yellow;">-p</mark> No port will default to port 0, not all ports. \ <mark style="color:yellow;">-S</mark> sets a syn only flag and will **syn scan** the port/ip. What we should see here is 2 syn packets being sent and, **if live, we will see a syn-ack and a rst flag** being set as the target responds to say the port is open then closes our stateful connection. \ <mark style="color:yellow;">-c</mark> says to only send 2 syn attempts The first is a rst-ack (closed). The second is a syn-ack (open)

### Classic Ping Sweep Scripts

{% tabs %}
{% tab title="PingSweep" %}

```bash
#!/bin/bash
for ip in $(seq 0 254); do
ping -c 1 192.168.31.$ip | grep "bytes from" |cut -d " " -f4 |cut -d ":" -f1 &
done
```

{% endtab %}

{% tab title="Bash1line" %}

```bash
for i {1..254} do ping -c 1 10.0.1.$i | fgrep ttl & done 2>/dev/null | sed -e 's/^.*from //' -e 's/:.*$//' | sort -n -t. -k4
```

{% endtab %}

{% tab title="Win" %}

```c
for /l %i in (1,1,254) do @ping -n 1 -w 100 10.185.11.%i
```

{% endtab %}
{% endtabs %}

## <mark style="color:orange;">Then start looking for low hanging fruit:</mark>

* Misconfigured servers
* Missing or bad ACLs
* Default or weak pass
* Open shares or null sessions allowed
* Broadcast requests
* Vulnerable to public exploits

{% hint style="success" %}
Once you have your hosts. Do some port scans against them with [NMAP](/reconnaissance/active-scanning/nmap.md) and [NSE](/reconnaissance/active-scanning/nmap/nse.md). Then hop on over to [Services](/initial-access/services.md) to start exploiting them with your Recon.&#x20;
{% endhint %}


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