Before understanding what is banner grabbing? One must understand what is a banner? Banners of a company or an institution are generally Enterprise Resource Planning (ERP) that holds information. The information available on the banner is mostly the data that is the primary source of information that feeds many other systems. The act of using a technique that helps to gain information about some system that is available on a certain network comes to be known as Banner Grabbing.

This technique can also be used to grab all the services running on the open ports of that particular system. Banner Grabbing attack is the term used when the hacker is to send a request to the system they are attempting to hack to gain more information and this can cause exploitation of the service, so for the security purpose, if there is no primary need for banner grabbing then it is removed by the company or the institution. In this article, you will learn about Banner Grabbing, the different techniques used for the same purpose, and Banner Grabbing Tools available to use the technique.  

  1. Definition
  2. Techniques
  3. Tools

1. Definition

Banner Grabbing is the term used to refer to the technique of grabbing information of a system available on a certain network and all the services running on its open ports. The Administrator can use this technique totally or take inventory of the system and its services on their available network. Banner hacking is often applicable for performing white hat hacking endeavors as well as for grey hacking.

This technique can gain information from banners and configurable text-based welcome screens from network hosts. These banners and network hosts generally contain information about the system. One of the important points of banner grabbing is that this technique is intended to be used by the administrator only. Few examples of service ports that are used for the Banner Grabbing technique are HyperText Transfer Protocol (HTTP), File Transfer Protocol (FTP), and Service Mail Transfer Protocol (SMTP). 

2. Techniques

There are two types of techniques available to perform Banner Grabbing. This section of the article will cover different techniques used for Banner Grabbing.

  1. Active Banner Grabbing: This technique is the most popular and the most widely used technique to do Banner Grabbing. In this type of Banner Grabbing, the packets are sent to the remote host and then they wait for the response to analyze the data. The sender can craft or modify the packets according to them. It involves the opening of a TCP (Transmission Control Protocol) connection or similar connection between an original host and the remote host. This type of Banner Grabbing is called active because the sender’s connection is logged into the remote host. Active Banner Grabbing may not prove secure always as while hacking, IDS (Intrusion Detection System) can catch the exploitation against the target computer or system.
  2. Passive Banner Grabbing: This technique, on the other hand, have is less risky than Active Banner Grabbing as in this technique, the high-level exposure to the connection is avoided. As the directed connection to the host is avoided and other intimidate Software and Systems are used as a gateway to connect. Passive Banner Grabbing can also tally all the information available on the system and this technique is much less risky than Active Banner Grabbing.

3. Tools

There are various kinds of tools available to perform the technique of Banner Grabbing. In this section of the article, Banner Grabbing tools are described, and below are some of the most popular and top tools available for using the Banner Grabbing technique.

  1. Telnet: It is the most popular and best tool for using the technique of banner Grabbing. Telnet web tool is the cross-platform that is available which helps to interact with remote servers for banner grabbing. Telnet allows querying any service, only by typing telnet IP PORT, where IP represents the IP address of the network and PORT represents the portal where the remote host is running.
  2. Wget: This tool is popularly used for Active Banner Grabbing, as this tool helps to connect to the remote host or the localhost. The syntax used for Wget is IP address -q -S, where IP address is the address of the network, -q will help to suppress the output, and -S is used as the parameter that will print the header file sent by the HTTPS server and FPS server.
  3. cURL: works exactly the same as Wget. It also connects to the remote host or the localhost but the only difference is in the syntax format. The syntax used for cURL is curl -s -I IP address | grep -e “Server:”, where -s is responsible for avoiding showing the process of error messages i.e. it mutes the output, -I am the parameter that is responsible for showing header file all the requested pages. At last, grep is used to get the final output from the server. 
  4. Nmap: It is an amazing tool to perform Banner Grabbing. It helps to get information from the targeted system in a very easy way. The syntax used to make use of Nmap is nmap –sV –version-intensity 5 site_name -p 80, where -sV allows to lean the software version, and writing –version-intensity 5, the sender can get the maximum information needed from the targeted system.
  5. NC: NetCat or NC is another tool used for fetching information using the banner grabbing technique. It is known to be the oldest and the most popular tool used on UNIX ad Linux. For using this tool, the syntax is written as nc -V IP POST. This helps in getting the FPS banner and the latest software version.
  6. ASR: ASR stands for Attack Surface Reduction and it is one the best tools available to reduce the attack area. ASR tool is considered ideal for IT managers and security leaders. This web tool will help in discovering unseen areas of your online assets. 

Conclusion

The technique of banner Grabbing can be used by the authorities to get credential information from some systems and can also be used by the non-ethical hackers who would try to invade and steal information from the targeted system for authorities. The former one is known as white hat hacking while the latter one is called grey hacking. Banner Grabbing helps tally the information available on a system by connecting to its host server. The banner grabbing technique is of two types, one is Active Banner Grabbing while the other one is Passive Banner Grabbing. There are several tools available for attempting Banner Grabbing. Few examples of these tools are telnet, cURL , Wget, etc. 

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