Author: Anamar Taknev

Hello, aspiring ethical hackers. In our previous blogpost, you learnt what is footprinting and various techniques used for footprinting. In this blogpost, you will learn about subfinder, a tool that helps us in footprinting.

Subfinder is a sub domain discovery tool that queries and retrieves valid sub domains for a given domain or website. It is a simple tool that uses passive subdomain enumeration for this purpose.

Let’s see how to use this tool to perform subdomain enumeration. For this, we will be using Kali Linux as our attacker machine. Subfinder can be installed on Kali as shown below.

The simplest method to use subfinder to query a sub domain of a particular domain is as shown below.

Specify multiple domains at once (-dL)

This tool can also query multiple domains at once. You can supply these domains using a file. For example, let’s create a new file “Domains.txt” and add a domain as shown below.

This file can be provided as input to subfinder as shown below.

View all the sources of this tool (-ls)

Subfinder collects information from a number of sources like AlienVault, Anubis, Censys, Shodan etc. You can view all the sources the subfinder tool queries using the command given below.

Query a single source (-s)

You can specify subfinder to query just one source using (-s) option as shown below. For example, let’s just specify GitHub and Anubis as sources.

Query all the sources (-all)

We can also specify this tool to query all the sources using the “-all” option.

Exclude some sources (-es)

We can even exclude some sources as shown below. For example, let’s exclude GitHub.

Display the source this tool queried in results (-cs)

We can even display source information to be displayed in output using the “-cs” option as shown below.

Saving output (-o)

You can save the output of this tool to a file as shown below.

Silent mode

In this mode, sub finder just displays the sub domains it found and nothing else.

Hello, aspiring ethical hacker. In our previous blogpost, you learnt about Denial of Service (DoS) attack. In this blogpost, you will learn about goldeneye, a HTTP DoS Test Tool.

This tool helps us to test if a web server is susceptible to DoS and DDoS attacks in real-world. Like any DoS testing tool, it generates a large number of requests in short time. Let’s see how this tool works. For this, we will use Kali Linux as this tool is available by default in its repositories. It can be installed as shown below. To install it on other systems, it can be downloaded from here.

The simplest way to use goldeneye tool is to just provide the URL you want to test as shown below.

Different modes (-m)

By default, goldeneye uses GET requests to test a website. However, it has two other modes too: POST and RANDOM. You can set this modes using the “-m” option.

Number of workers (-w)

By default, goldeneye uses 10 workers running 500 connections each. However, we can change it using the “-w” option. For example, let’s set it to 20 workers.

Number of connections (-s)

Similarly, we can change the number of connections using the “-s” option. Let’s change the number of connections to 1000.

Debug mode(-d)

We can run goldeneye tool in debug mode using the “-d” option. Debug mode gives detailed information about the tests being performed.

Hello, aspiring ethical hackers. In this blogpost, you will learn about a tool called Lynis, the security auditing and hardening tool for UNIX based systems like Linux, macOS, BSD and others. It performs an in-depth security scan to test security defenses and provide suggestions for further system hardening.

This tool audits the following features on the system.

1. General system information.
2. System tools.
3. Operating system.
4. Boot and other services.
5. Kernel vulnerabilities.
6. Memory and processes.
7. Users, groups and authentication
8. Kerberos
9. Shells
10. File systems
11. USB devices
12. Storage
13. NFS
14. Name Services
15. Ports and packages
16. Networking
17. Printers and Spool
18. Email and messaging software
19. Firewalls
20. Web servers
21. SSH and SNMP
22. Databases
23. PHP (in web server)
24. Logging and log files
25. Insecure services
26. Banners
27. Scheduled Tasks
28. Accounting
29. Time and synchronization
30. Cryptography
31. Virtualization
32. Containers
33. Security frameworks
34. System tools and malware
35. File permissions etc.

Let’s see how to run Lynis for the first time. For this, we will be using Kali Linux. It can be installed on Kali as shown below.

After the installation is successful, run the command shown below to run it to audit the entire system.

lynis audit system

It runs as shown below.

While auditing, wherever there is scope for hardening, lynis adds a suggestion as shown below.

After the entire system is audited, Lynis provides summary of the entire audit as shown below.

Below the summary, you can find each suggestion as shown below.

You can harden your system based on these suggestions. You can also find this information in the log reports of Lynis.

Hello aspiring ethical hackers. In our previous blogpost, you studied about website footprinting. In this blogpost, you will learn about a tool called eyewitness which helps you to decide which website to focus on.

In ethical hacking, before trying to footprint a website, it would be good if we have a general idea about what websites to target first. For example, a company you are going to pen test may have multiple websites and sub domains. Before we jump into password cracking or exploitation or directory busting or perform any other attack, it would be good if we are first able to decide what website and URLs to target first. The role of eyewitness tool comes there. Eyewitness takes the screenshots of the URLs or websites you provide. Apart from taking screenshot of the URL, it will also capture any header info and default passwords.

Let’s see how to use this tool. For this we will be using Kali Linux as this tool is available by default in Kali repositories. As target, we will be using Metasploitable 2 installed in our virtual hacking Lab. It can be installed as shown below.

Target a single URL (–single)

You can take screenshot of a single URL as shown below.

As soon as it writes a report for your target, it will ask you if you want to open the report. Click on “Yes”. It will open the report as shown below.

You can even view the code of the URL you scanned.

But the real power of eyewitness can be seen when we are targeting multiple URLs at once. For doing this, we will first create a file called URLS.txt and add some URLs we want to target as shown below.

Target multiple URLs (-f)

Multiple URLs can be targeted with this tool by specifying the above created file with (-f) option.

Here’s the report.

One of our URLs we targeted ended up in a error.

Skip DNS resolution(–no-dns)

In some cases, while using eyewitness tool, you may have to go through a VPN. In such cases, it is good to skip DNS resolution when connecting to the website. This option helps you to do it.

Resolve IP / host name for your target (–resolve)

Time to wait while requesting an URL (–timeout)

By default, eyewitness waits for 7 seconds before it goes to take a screenshot of a new webpage. However, this can be changed with this option. For example, let’s change the timeout time to 1 second.

Add jitter (–jitter)

Using this option, we can randomize the URLs specified and add a random delay.

Add delay before taking a screenshot (–delay)

Using the option, we can add delay between opening of the navigator and taking a screenshot. This delay can be specified in seconds. For example, let’s add 10 seconds delay before taking screenshot.

Maximum retries (–max-retries)

This option specifies eyewitness tool how many retries it has to make if it fails to grab a screenshot on the first attempt.

Specify directory name for saving the report (-d)

This option is used to specify a directory name for saving the report.

Number of results to show on one page (–results)

By default, eyewitness shows output for all the URLs given as input on a single page. This option can be used to specify how many results to show per page. For example, let’s set it to show 1 result per page.

As you can see, now, all the results are shown on separate pages.

You don’t want to be prompted for viewing the report (–no-prompt)

If you don’t want eyewitness to prompt you to open the report after finishing its work, you can use this option.

Hello, aspiring ethical hackers. In our previous blogpost, you have learnt about network scanning and enumeration. In this blogpost, you will learn about a tool named arp scan, a command line tool used for scanning and fingerprinting on the local network.

ARP scan is available for Linux and BSD systems and uses ARP protocol to scan the network. Let’s see how to use this tool. For this, we will be using Kali Linux as this tool is available for download by default in Kali repositories.

It is good to run arp scan tool as root user in order not to face some errors. You can simply scan a network using arp-scan as shown below.

If you want to scan your local network, you can simply specify the “-r” option to do it as shown below.

If your device is connected to multiple networks and you want to scan a particular network, you can specify the network interface using the “-I” option. By default if the “-I” option is not specified, arp-scan will search the system interface list for the lowest numbered configured up interface, excluding Loopback and scan that network.

Quiet mode (-q)

If you want minimal output to be displayed for each responding host, while scanning with arp-scan, you can use quiet mode. While using this mode, only the target IP address and MAC address are displayed.

Plain mode (-x)

If you want more less details like just the responding host details, you can use the plain mode. While using this mode, arp scan suppresses the header and footer text in output as shown below.

Ignore duplicates (-g)

By default, arp scan displays duplicate packets by flagging them with (DUP.n) where “n” is the number of times the target host responded. By specifying the option, these duplicate packets can be ignored by arp-scan.

Calculate and display round trip time (-D)

Network Packet round trip time (RTT) is the time it takes for a data packet to travel from a source to a destination and back again. It is a key matric to measure network latency and is usually measured in milliseconds. Setting this option, allows us to measure the round trip time.

Retry attempts (-r)

This option can be used to specify the number of retry attempts to make per host. By default arp-scan makes 2 retry attempts. For example let’s set it to 3.

timeout (-t)

By default, 500ms is the timeout for this tool. This option can be used to change it however.

Interval (-i)

If you have limited bandwidth to use for scanning with this tool, you can use this option to control the outgoing bandwidth by limiting the packet rate. For example, let’s set the interval between each packet to 400 milliseconds. It can also be set to micro seconds by appending the “u” option.

Bandwidth (-B)

This option is useful when you want to control the outbound bandwidth to a specific value. By default, bandwidth is 2,46,000 bits per second.

Resolve responding addresses to hostnames (-d)

This option is used to resolve the hostnames for addresses detected by this tool. The default output format will display the hostnames instead of the IPv4 address.

Limit the number of hosts to scan (-M)

By default, arp-scan scans all the hosts on the network that are LIVE. You can limit the number of hosts to scan using this option.