What is a bot? What is a botnet?

Definition of the term "Bot"

A bot is a computer program designed to automatically perform certain tasks repeatedly, often faster and more precisely than a human could. The term "bot" derives from "robot". Bots can be both useful and harmful and play a significant role on the internet.

Useful Bots

Useful bots support us in many areas of digital life. For example, they search the internet as search engine bots (also called webcrawlers) to index content for search queries. Chatbots simulate human conversations and provide quick customer service or answers to frequently asked questions.

There are also good bots in offensive IT security. For example, you can look at eASM Argos - it controls hundreds of bots (which are nothing more than small servers) and performs automated attacks on websites to find vulnerabilities and report them to the client. It monitors changes and can thus respond to new threats.

Harmful Bots

Harmful bots, on the other hand, are used by cybercriminals and APTs to gain unauthorized access to systems, steal data, or conduct attacks. These bots can monitor network communication, execute commands, or launch coordinated attacks as part of a botnet.

What types of bots are there?

Bots can be categorized into different types depending on the tasks they perform and the intention with which they are deployed. Here are some common types of bots:

1. Search Engine Bots:
   These bots search the internet to index content for search engines. Everyone knows the bots from Google, Microsoft, or Amazon.
2. Harvester Bots:
   This type of bot searches the internet for specific information - such as email addresses or phone numbers. These are often subsequently used for spam messages or phishing attacks. Companies like hunter.io offer this data as a service/API.
3. Chatbots:
   Programs that simulate human conversations and are often used in customer service. Nowadays, these bots often use LLM applications to provide users with a better experience.
4. Registration Bots:
   They automatically register for internet services, for example to create email accounts. Here too, the background is often sending spam or manipulating opinions.
5. Spambots:
   Bots that send spam messages to collected email addresses.
6. DDoS Bots:
   They conduct coordinated attacks on servers to disable services. This category also includes IoT bots that infect insecure devices like routers or cameras. Generally, any bot that conducts attacks belongs in this category.
7. Social Bots:
   Social bots operate in social networks to exert influence. They can spread content, increase follower numbers, or manipulate content through fake reviews and comments.

Malicious Bots

Malicious bots also include those that attempt to access accounts using stolen credentials, or bots that search websites for personal data.

What is a Botnet?

A botnet is a network of many infected PCs, routers, smartphones, or IoT devices controlled by a bot master. Many of the devices became part of the botnet through the exploitation of known vulnerabilities. Backdoors and malware have been installed on most of these devices. These networked bots can be coordinated together to conduct large-scale attacks such as Distributed Denial of Service (DDoS) attacks or send spam on a large scale.

Bot Master and Control

The bot master controls the botnet through backdoor programs and can thus send commands to the infected systems without the device owners noticing.

How can you protect yourself from bots?

Protection against unwanted bots is an important aspect of IT security. There are various measures to protect against harmful bots and prevent their activities.

1. Use of CAPTCHAs:
   CAPTCHAs ensure that only human users can access certain services by presenting tasks that are difficult for bots to solve.
2. Use of Honeypots:
   Honeypots are traps for bots that analyze their behavior and allow their activities to be detected.

Bot Management Solutions

Specialized bot management software can identify and block harmful bots without affecting the experience of legitimate users. Such solutions often use machine learning to distinguish between human users, useful bots, and harmful bots.

At the DNS level, companies like Akamai and Cloudflare can already block bots before their HTTP requests reach a website or service. These solutions are particularly effective against DDoS attacks and protect websites from overload.

Regular Security Updates

Software should generally always be kept up to date. Security updates ensure that bots cannot exploit vulnerabilities. The risk of successful attacks by bots is minimized - but you have to be quick here. After vulnerabilities are published, it sometimes takes only minutes before the first bots begin their attacks.