Tryhackme | Nmap

Nehru G
5 min readJan 6, 2022

#Task -1 Deploy

  1. Deploy the attached VM

Answer:- No need Answer

#Task -2 Introduction

2.1-What networking constructs are used to direct traffic to the right application on a server?

Answer:- ports

2.2-How many of these are available on any network-enabled computer?

Answer:-65535

2.3-[Research] How many of these are considered “well-known”? (These are the “standard” numbers mentioned in the task)

Answer:-1024

#Task -3 Nmap Switches

3.1-What is the first switch listed in the help menu for a ‘Syn Scan’ (more on this later!)?

Answer: — sS

3.2-Which switch would you use for a “UDP scan”?

Answer:- -sU

3.3-If you wanted to detect which operating system the target is running on, which switch would you use?

Answer:- -O

3.4-Nmap provides a switch to detect the version of the services running on the target. What is this switch?

Answer:- -sV

3.5-The default output provided by nmap often does not provide enough information for a pentester. How would you increase the verbosity?

Answer: -v

3.6-Verbosity level one is good, but verbosity level two is better! How would you set the verbosity level to two?
(Note: it’s highly advisable to always use at least this option)

Answer: -vv

3.7-We should always save the output of our scans — this means that we only need to run the scan once (reducing network traffic and thus chance of detection), and gives us a reference to use when writing reports for clients.

What switch would you use to save the nmap results in three major formats?

Answer: -oA

3.8 -What switch would you use to save the nmap results in a “normal” format?

Answer: -oN

3.9-A very useful output format: how would you save results in a “grepable” format?

Answer: -oG

3.10-Sometimes the results we’re getting just aren’t enough. If we don’t care about how loud we are, we can enable “aggressive” mode. This is a shorthand switch that activates service detection, operating system detection, a traceroute and common script scanning.

How would you activate this setting?

Answer: -A

3.11-Nmap offers five levels of “timing” template. These are essentially used to increase the speed your scan runs at. Be careful though: higher speeds are noisier, and can incur errors!

How would you set the timing template to level 5?

Answer: -T5

3.12-We can also choose which port(s) to scan.

How would you tell nmap to only scan port 80?

Answer: -p 80

3.13-How would you tell nmap to scan ports 1000–1500?

Answer: -p 1000–1500

3.14-A very useful option that should not be ignored:

How would you tell nmap to scan all ports?

Answer: -p-

3.15-How would you activate a script from the nmap scripting library (lots more on this later!)?

Answer: — script

3.16-How would you activate all of the scripts in the “vuln” category?

Answer: — script=vuln

#Task- 4 Scan Types Overview

4.1-Read the Scan Types Introduction.

Answer : No Need Answer

#Task -5 Scan Types TCP Connect Scans

5.1- Which RFC defines the appropriate behaviour for the TCP protocol?

Answer:RFC 793

5.2-If a port is closed, which flag should the server send back to indicate this?

Answer: RST

#Task -6 Scan Types SYN Scans

6.1-There are two other names for a SYN scan, what are they?

Answer:Half-Open, Stealth

6.2-Can Nmap use a SYN scan without Sudo permissions (Y/N)?

Answer:N

#Task- 7 Scan Types UDP Scans

7.1-If a UDP port doesn’t respond to an Nmap scan, what will it be marked as?

Answer: open|filtered

7.2-When a UDP port is closed, by convention the target should send back a “port unreachable” message. Which protocol would it use to do so?

Answer:ICMP

#Task -8 Scan Types NULL, FIN and Xmas

8.1-Which of the three shown scan types uses the URG flag?

Answer: ICMP

8.2-Why are NULL, FIN and Xmas scans generally used?

Answer: Firewall Evasion

8.3-Which common OS may respond to a NULL, FIN or Xmas scan with a RST for every port?

Answer: Microsoft Windows

#Task- 9 Scan Types ICMP Network Scanning

9.1-How would you perform a ping sweep on the 172.16.x.x network (Netmask: 255.255.0.0) using Nmap? (CIDR notation)

Answer: nmap -sn 172.16.0.0/16

#Task -10 NSE Scripts Overview

10.1-What language are NSE scripts written in?

Answer: Lua

10.2-Which category of scripts would be a very bad idea to run in a production environment?

Answer:intrusive

#Task -11 NSE Scripts Working with the NSE

11.1-What optional argument can the ftp-anon.nse script take?

Answer:maxlist

#Task -12 NSE Scripts Searching for Scripts

12.1-Search for “smb” scripts in the /usr/share/nmap/scripts/ directory using either of the demonstrated methods.
What is the filename of the script which determines the underlying OS of the SMB server?

Answer:smb-os-discovery.nse

12.2-Read through this script. What does it depend on?

Answer:smb-brute

#Task- 13 Firewall Evasion

13.1-Which simple (and frequently relied upon) protocol is often blocked, requiring the use of the -Pn switch?

Answer: ICMP

13.2-[Research] Which Nmap switch allows you to append an arbitrary length of random data to the end of packets?

Answer: — data-length

#Task -14 Practical

14.1-Does the target (MACHINE_IP)respond to ICMP (ping) requests (Y/N)?

Answer: N

14.2-Perform an Xmas scan on the first 999 ports of the target — how many ports are shown to be open or filtered?

Answer: 999

14.3-There is a reason given for this — what is it?

Note: The answer will be in your scan results. Think carefully about which switches to use — and read the hint before asking for help!

Answer: No Response

14.4-Perform a TCP SYN scan on the first 5000 ports of the target — how many ports are shown to be open?

Answer: 5

14.5-Open Wireshark (see Cryillic’s Wireshark Room for instructions) and perform a TCP Connect scan against port 80 on the target, monitoring the results. Make sure you understand what’s going on.

Answer: No need Answer

14.6-Deploy the ftp-anon script against the box. Can Nmap login successfully to the FTP server on port 21? (Y/N)

Answer:y

#Task -15 Conclusion

15.1- Read the conclusion.

Answer: DOne!

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