What is a spambot?

The term spambot is a compound word combining the word “spam”—an unsolicited message transmitted electronically—and “bot,” the term used to refer to a computer program that mostly performs automated tasks. Spambots are used for the mass and automated distribution of messages and comments on websites and social media.

How a spam bot works


A definition of spambot

Bots are computer programs that perform repetitive tasks without human intervention and run on the internet. A spambot is a malicious type of bot specifically programmed to send spam messages in bulk. A spambot can also independently post spam to various places on the internet where people interact online, such as social media or forums.

Spam refers to inappropriate or unsolicited messages sent to numerous recipients. They usually contain unwanted product advertisements, irrelevant backlinks used to improve the ranking of the linked website in search engine results, or fraudulent messages with dangerous links or malware attached to them.


How does a spambot get onto a computer?

A spambot is a malicious program that stealthily infects systems and acts without the knowledge of the user. Common methods of infecting a targeted system include, but are not limited to:

  • Installation via Trojan: The user downloads a seemingly harmless program with a bot embedded in it, which it then installs in the background. This is the method most commonly employed.

  • Exploits: The attacker is aware of a vulnerability in the operating system or an application, such as a web browser. By exploiting it, he installs the bot on the target system without being noticed.

  • Installation via e-mail: The user receives an e-mail including a link and is encouraged to install the linked software. Occasionally, the link does not download a program, but instead directs the user to a malicious website, which then attempts to exploit a variety of vulnerabilities in the web browser using the “drive-by infection” method, thereby installing a bot.

  • Automatic distribution via bots: Some bots are specifically programmed to search for vulnerabilities in other systems to find out whether new bots can be injected via exploits.


How different kinds of spambots work

Form spam

Bots are basically nothing more than scripts that independently perform predefined tasks. They can, for example, automatically comb the internet for websites that include forms, e-mail addresses, and other information. In the process, the spambot jumps from page to page by following the links embedded in them. In this respect, spambots are no different from their benign “colleagues.” Google Spider, to take just one example, is no different. It visits a web page, analyzes the content, sends information to Google’s servers, and then continues to the next page. An important differentiator between the two types of bots is their behavior when it comes to forms. Google bots do not fill out forms, but some spambots do.

Account creation & takeover

This allows malicious bots to create fake accounts on forums, social media platforms, in messaging apps, or with e-mail hosting providers. They can do this because creating an account often only requires filling out a few fields, such as the name or e-mail address. Attackers program their spambots to automatically fill out these forms. Some platforms employ CAPTCHAs or similar hurdles to prevent just this from happening, but these protections are not foolproof. Once the fake account is created by the spambot or another form of access to a platform is found, the bots start sending spam messages following a set of rules previously defined by the bot programmer.

To make this possible, other types of spambots engage in important preliminary work by collecting e-mail addresses or telephone numbers, which are then misused to send spam. This involves searching the internet, gathering contact information, and storing it in a database.

Spambots are programmed to work rapidly while consuming as few resources as possible. There are economic reasons for this: Operating a spam server incurs costs that must be recouped based on the principle of “mass, not class.” The goal is therefore to send as many spam messages as possible. Numerous bot instances run concurrently on each server and browse the internet simultaneously. To run more bots on each server, bots use simple requests sent to web servers. The returned HTML code is then analyzed. The accompanying CSS or JavaScript code is usually not interpreted to save resources and time.


Methods for identifying spambots

Spambots are only successful if they can perform their tasks while remaining undetected. During execution, for example, when entering spam messages into a comment form, they mimic the behavior of human users. Nevertheless, the activities of spambots can be detected using several methods:


The speed of spambots in particular can help distinguish access by malware from that of real people: Human visitors to a website typically take a certain amount of time to fill out a contact or comment form. In any case, if a human is involved, more than ten seconds should elapse between visiting a page and submitting the form. Bots, however, take only a few seconds for the same process. Timestamps can be used to measure how much time users spend on the website before completing and submitting the form. This time interval allows conclusions to be made as to whether the form was actually filled out by a human. The use of timestamps is an effective method of identifying spambots and preventing them from doing things like posting comments. Since human websites visitors do not have to become actively involved in this process, this is a user-friendly alternative to CAPTCHAs.


A honeypot is part of a website deliberately rendered invisible to human visitors. For example, a honeypot in the form of an additional input field is integrated into a form and then hidden using CSS or JavaScript. Humans always focus on the layout of the website and don’t fill out what they are unable to see. A spambot, on the other hand, focuses on the source code of the website. Since it is unable to recognize whether a specific input field is visible, it always fills in every field, including the honeypot. When the form is then submitted and processed, a short query whether or not the honeypot field has been filled in is all it takes to detect a bot.


Problematic, undesirable, and dangerous access by spambots can also be detected using “fingerprints.” When Myra Hyperscale WAF is used, for example, each time the website is accessed, more than 50 access attributes for the unique identification of the system used are included in the fingerprint. Myra has now stored over three million of these digital fingerprints. As soon as the fingerprint is obtained, appropriate measures can be taken and protective mechanisms initiated. Unwanted and prohibited access can be clearly identified, blocked, confronted with human interaction challenges such as CAPTCHAs, or otherwise controlled or redirected.

Code on a screen


How can you protect yourself from spambots?

Botnets pose a significant threat. Companies should certainly divide, classify, and analyze incoming requests to detect an attempted attack with spam malware in good time and be able to take appropriate action.

The Myra Web Application Security portfolio includes all the products and services needed to effectively protect websites and applications from malicious bot access:

  • Myra Deep Bot Management is modular in design and provides full flexibility in detecting and controlling bots, either based on bot categories or as a complete package. Myra Multi-Fingerprinting is an integral part of the system for reliably detecting automated bot accesses.

  • The Myra Hyperscale WAF filters, monitors, and controls incoming and outgoing web traffic on the content level. This enables applications to be protected against the infiltration of malicious data and the spying out of sensitive information, among other things.

Person works on a laptop


What you need to know about spambots

A spambot is a malicious type of bot specifically programmed to send spam messages in bulk. A spambot can independently post spam to various places on the internet where people interact online, such as social media or forums. Spambots work behind the scenes and can be detected by their non-human approach, when automatically filling out web forms, for instance. But bots leave traces behind. Their clear identification is the basis for managing them effectively, for example, by using protection solutions with fingerprint detection: you can protect yourself preemptively against this form of malware.