7 Nmap NSE Scripts for Recon

These Nmap NSE Scripts are all included in standard installations of Nmap.

Use them to gather additional information on the targets you are scanning. The information can both add context to the hosts you are scanning and widen the attack surface of the systems you are assessing.

Information Gathering

1. DNS Brute Force

Find sub-domains with this script. Detecting sub-domains associated with an organizations domain can reveal new targets when performing a security assessment. The discovered hosts may be virtual web hosts on a single web server or may be distinct hosts on IP addresses spread across the world in different data centres.

The dns-brute.nse script will find valid DNS A records by trying a list of common sub-domains and finding those that successfully resolve.

nmap -p 80 --script dns-brute.nse vulnweb.com

Starting Nmap 6.46 ( http://nmap.org ) at 2014-09-24 19:58 EST
Nmap scan report for vulnweb.com (176.28.50.165)
Host is up (0.34s latency).
rDNS record for 176.28.50.165: rs202995.rs.hosteurope.de
PORT   STATE SERVICE
80/tcp open  http

Host script results:
| dns-brute: 
|   DNS Brute-force hostnames: 
|     admin.vulnweb.com - 176.28.50.165
|     firewall.vulnweb.com - 176.28.50.165
|_    dev.vulnweb.com - 176.28.50.165

Nmap done: 1 IP address (1 host up) scanned in 28.41 seconds

2. Find Hosts on IP

Another tactic for expanding an attack surface is to find virtual hosts on an IP address that you are attempting to compromise (or assess). This can be done by using the hostmap-* scripts in the NSE collection. The hostmap-bfk.nse seems to work reasonably well providing a good starting point for your recon (IP to Host services do vary in accuracy).

nmap -p 80 --script hostmap-bfk.nse nmap.org

Starting Nmap 6.46 ( http://nmap.org ) at 2014-09-24 19:47 EST
Nmap scan report for nmap.org (173.255.243.189)
Host is up (0.19s latency).
PORT   STATE SERVICE
80/tcp open  http

Host script results:
| hostmap-bfk: 
|   hosts: 
|     www.nmap.org
|     173.255.243.189
|     seclists.org
|     sectools.org
|     svn.nmap.org
|     nmap.org
|     hb.insecure.org
|     insecure.org
|     images.insecure.org
|     189.243.255.173.in-addr.arpa
|_    www.insecure.org

Nmap done: 1 IP address (1 host up) scanned in 2.10 seconds

3. Traceroute Geolocation

Perform a traceroute to your target IP address and have geolocation data plotted for each hop along the way. Makes correlating the reverse dns names of routers in your path with locations much easier.

sudo nmap --traceroute --script traceroute-geolocation.nse -p 80 hackertarget.com

Starting Nmap 6.46 ( http://nmap.org ) at 2014-09-24 21:03 EST
Nmap scan report for hackertarget.com (178.79.163.23)
Host is up (0.31s latency).
PORT   STATE SERVICE
80/tcp open  http

Host script results:
| traceroute-geolocation: 
|   HOP  RTT     ADDRESS                                                GEOLOCATION
|   1    2.09    192.168.1.1                                            - ,- 
|   2    25.55   core-xxxxx.grapevine.net.au (203.xxx.32.20)            -27,133 Australia (Unknown)
|   3    31.61   core-xxxxx.grapevine.net.au (203.xxx.32.25)            -27,133 Australia (Unknown)
|   4    25.02   xe0-0-0-icr1.cbr2.transact.net.au (202.55.144.117)     -27,133 Australia (Unknown)
|   5    23.48   xe11-3-0.cr1.cbr2.on.ii.net (150.101.33.62)            -27,133 Australia (Unknown)
|   6    43.45   ae2.br1.syd4.on.ii.net (150.101.33.22)                 -27,133 Australia (Unknown)
|   7    175.24  te0-0-0-1.br1.lax1.on.ii.net (203.16.213.69)           -27,133 Australia (Unknown)
|   8    181.29  TenGE13-2.br02.lax04.pccwbtn.net (206.223.123.93)      38,-97 United States (Unknown)
|   9    310.46  telecity.ge9-9.br02.ldn01.pccwbtn.net (63.218.13.222)  51,0 United Kingdom (London)
|   10   309.63  212.111.33.238                                         51,0 United Kingdom (Unknown)
|_  11   338.95  hackertarget.com (178.79.163.23)                       51,0 United Kingdom (Unknown)

TRACEROUTE (using port 80/tcp)
HOP RTT       ADDRESS
1   2.09 ms   192.168.1.1
2   25.55 ms  core-xxxxx.grapevine.net.au (203.xxx.32.20)
3   31.61 ms  core-xxxxx.grapevine.net.au (203.xxx.32.25)
4   25.02 ms  xe0-0-0-icr1.cbr2.transact.net.au (202.55.144.117)
5   23.48 ms  xe11-3-0.cr1.cbr2.on.ii.net (150.101.33.62)
6   43.45 ms  ae2.br1.syd4.on.ii.net (150.101.33.22)
7   175.24 ms te0-0-0-1.br1.lax1.on.ii.net (203.16.213.69)
8   181.29 ms TenGE13-2.br02.lax04.pccwbtn.net (206.223.123.93)
9   310.46 ms telecity.ge9-9.br02.ldn01.pccwbtn.net (63.218.13.222)
10  309.63 ms 212.111.33.238
11  338.95 ms hackertarget.com (178.79.163.23)

HTTP Recon

Nmap comes with a wide range of NSE scripts for testing web servers and web applications. An advantage of using the NSE scripts for your HTTP reconnaissance is that you are able to test aspects of a web server against large subnets. This can quickly provide a picture of the types of servers and applications in use within the subnet.

4. http-enum.nse

One of the more aggressive tests, this script effectively brute forces a web server path in order to discover web applications in use. Attempts will be made to find valid paths on the web server that match a list of known paths for common web applications. The standard test includes testing of over 2000 paths, meaning that the web server log will have over 2000 entries that are HTTP 404 not found, not a stealthy testing option! This is very similar to the famous Nikto web server testing tool (that performs 6000+ tests).

nmap --script http-enum 192.168.10.55

Nmap scan report for ubuntu-test (192.168.10.55)
Host is up (0.024s latency).
Not shown: 993 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
25/tcp   open  smtp
80/tcp   open  http
| http-enum: 
|   /robots.txt: Robots file
|   /readme.html: WordPress version 3.9.2
|   /css/: Potentially interesting directory w/ listing on 'apache/2.2.22 (ubuntu)'
|   /images/: Potentially interesting directory w/ listing on 'apache/2.2.22 (ubuntu)'
|_  /js/: Potentially interesting directory w/ listing on 'apache/2.2.22 (ubuntu)'

Additional options:

Specify base path, for example you could specify a base path of /pub/.

nmap --script -http-enum --script-args http-enum.basepath='pub/' 192.168.10.55

Nmap scan report for xbmc (192.168.1.5)
Host is up (0.0012s latency).
PORT   STATE SERVICE
80/tcp open  http
| http-enum: 
|   /pub/: Root directory w/ listing on 'apache/2.2.22 (ubuntu)'
|   /pub/images/: Potentially interesting directory w/ listing on 'apache/2.2.22 (ubuntu)'
|_  /pub/js/: Potentially interesting directory w/ listing on 'apache/2.2.22 (ubuntu)'

Nmap done: 1 IP address (1 host up) scanned in 1.03 seconds

5. HTTP Title

It is not a difficult thing to find the Title of the web page from a web server, this script just makes it easier to get those title's in one set of results from a range of IP addresses.

Having the title of the page included in the Nmap scan results can provide context to a host, that may identify the primary purpose of the web server and whether that server is a potential attack target.

nmap --script http-title -sV -p 80 192.168.1.0/24

Starting Nmap 6.46 ( http://nmap.org ) at 2014-09-24 20:47 EST
Nmap scan report for 192.168.1.1
Host is up (0.0018s latency).
PORT   STATE SERVICE VERSION
80/tcp open  http    Linksys wireless-G WAP http config (Name RT-N16)
|_http-title: 401 Unauthorized
Service Info: Device: WAP

Nmap scan report for xbmc (192.168.1.115)
Host is up (0.0022s latency).
PORT   STATE SERVICE VERSION
80/tcp open  http    Apache httpd 2.2.22 ((Ubuntu))
|_http-title: Site doesn't have a title (text/html).

Nmap scan report for 192.168.1.118
Host is up (0.0035s latency).
PORT   STATE SERVICE VERSION
80/tcp open  upnp    Epson WorkForce 630 printer UPnP (UPnP 1.0; Epson UPnP SDK 1.0)
|_http-title: WorkForce 630
Service Info: Device: printer; CPE: cpe:/h:epson:workforce_630

Service detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 256 IP addresses (8 hosts up) scanned in 10.17 seconds

Microsoft Windows Network Recon

Find operating systems, users, processes and more from systems within your local windows network with these information gathering scripts. Generally these smb-* scripts will get you a lot more information if you have valid credentials. However, with even Guest or Anonymous access you will usually be able to at least expand your knowledge of the network.

6. smb-os-discovery.nse

Determine operating system, computer name, netbios name and domain with the smb-os-discovery.nse script. An example use case could be to use this script to find all the Windows XP hosts on a large network, so they can be unplugged and thrown out (Windows XP is no longer supported by Microsoft). The key advantage to using Nmap for something like this rather than a Microsoft native tool is that it will find all systems connected to the network not just those attached to a domain.

nmap -p 445 --script smb-os-discovery 192.168.1.0/24

Starting Nmap 6.46 ( http://nmap.org ) at 2014-09-24 23:32 EST

Nmap scan report for test1 (192.168.1.115)
Host is up (0.0035s latency).
PORT    STATE SERVICE
445/tcp open  microsoft-ds

Host script results:
| smb-os-discovery: 
|   OS: Unix (Samba 3.6.3)
|   Computer name: ubuntu003
|   NetBIOS computer name: 
|   Domain name: 
|   FQDN: ubuntu003
|_  System time: 2014-09-24T23:34:41+10:00

Nmap scan report for 192.168.1.101
Host is up (0.018s latency).
PORT    STATE SERVICE
445/tcp open  microsoft-ds

Host script results:
| smb-os-discovery: 
|   OS: Windows XP (Windows 2000 LAN Manager)
|   OS CPE: cpe:/o:microsoft:windows_xp::-
|   Computer name: test-xp3
|   NetBIOS computer name: TEST-XP3
|   Workgroup: WORKGROUP
|_  System time: 2014-09-24T23:33:01+01:00

7. smb-brute.nse

Another example of the smb series of NSE scripts is the smb-brute.nse that will attempt to brute force local accounts against the SMB service.

While I would not classify brute forcing accounts as a recon function of the assessment process this script can lead to large amount of recon if we do get valid credentials as there are other smb-* scripts that can be leveraged to retrieve all local user accounts smb-enum-users.nse, groups smb-enum-groups.nse, processes smb-enum-processes.nse and even execute processes remotely with the smb-psexec.nse script.

nmap -sV -p 445 --script smb-brute 192.168.1.101

Starting Nmap 6.46 ( http://nmap.org ) at 2014-09-24 23:47 EST
Nmap scan report for 192.168.1.101
Host is up (0.060s latency).
PORT    STATE SERVICE      VERSION
445/tcp open  microsoft-ds Microsoft Windows XP microsoft-ds
Service Info: OS: Windows; CPE: cpe:/o:microsoft:windows

Host script results:
| smb-brute: 
|_  No accounts found

Service detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 115.04 seconds

As can be seen in the example above we have not found any accounts. So lets take a look at the activity on the wire while the smb-brute.nse script was running.

Nmap NSE SMB Brute Wireshark Capture

It is pretty clear from this Wireshark capture that sessions were being established and a large number of account credentials were being tested.

Digging deeper and finding Gold with Nmap NSE scripts

After this quick skim of the capabilities of a sample of the Nmap NSE scripts. My suggestion is to look a bit deeper. There are literally hundreds of scripts now available and included in a regular Nmap installation. Each of the .nse files comes with pretty good documentation right there in the script or more information can be found on the NSE scripts documentation portal.

Find the NSE scripts location for your Nmap installation locate nse | grep scripts and take a look through the included scripts. There are many surprising finds; not only for reconnaissance but also scripts for discovery of exploitable services.

  Updated: 21 May 2018