What are bots and how to prevent them

What Are Bots and How to Prevent Them

Modern-day bots present businesses with a catch-22 situation. For every two bots that are helpful, like chatbots and web crawlers, there are another three that are malicious, like spambots, fraud bots, and the all-encompassing botnets, just to name a few. 

Yet, if your business attempts to ban every bot, you’ll ultimately do more harm than good. 

All internet traffic comes from humans or bots. A global analysis of automated bot traffic revealed that bots are responsible for nearly half of all traffic across the internet. Some of these bots are beneficial, chatting with customers and crawling your site to scan and index your content. It's counterintuitive to prevent them from accessing your website. 

But what about harmful bots? How do you detect malicious bots that are creating fake accounts, committing fraud, or compromising user accounts? 

First, let's answer this question: What are bots, anyway? 

In this comprehensive 101-level guide, you'll learn what bots are, the different types of bots, and how to detect a malicious bot and prevent an attack. 

What is a bot? 

Bots are software applications that use machine learning (ML) to perform specific tasks without human intervention. They typically replicate human activity, completing repetitive tasks faster. Bots can also connect different application programming interfaces (APIs) to simplify and automate workflows. 

Types of bots

Some bots are useful, the so-called good bots, while others are inherently bad or malicious. Here’s how they can impact your business.

Good bots

These are applications that positively impact business performance without harming customers or internet users. Good bots optimize existing resources and save human employees time by taking care of tedious tasks. They can even improve the customer experience. 

For instance, many organizations use bots for customer self-service, such as chatbots that reduce help center wait times and shopping bots that ramp up conversions. Types of good bots include:

• Chatbots: Also referred to as smart assistants and knowledge chatbots depending on their programming capabilities, chatbots imitate human conversation through a combination of artificial intelligence (AI) and ML. They can respond to customer support queries and direct users to relevant content, such as related blog posts or how-to guides.

• Monitoring bots: These bots track unusual activity, bugs, malicious software, and similar vulnerabilities by monitoring user behavior and web traffic. They help prevent potential data security incidents.

• Shopping bots: Shopping bots scrape product pricing across multiple websites and platforms to help users locate the best value for money. They can also deliver personalized recommendations. 

• Social media bots: These bots engage with content on social media like real people. They provide quick updates, like sports scores but can also artificially inflate a user’s likes and follower count.

• Web crawlers: Also known as scrapers, spiders, search engine bots, and Googlebots, web crawlers scan and index content on the internet, helping search engines like Google produce more relevant search results. They can also be used independently to monitor product pricing or track customer sentiment over time.

Malicious bots

Malicious bots (or malware bots) are applications designed to misuse business and personal data. While bots that attempt to conduct cybercrime are always considered malicious, not every type of bad bot has to break the law to be labeled as such.

For instance, any bot that violates a website’s terms of service or robots.txt rules for bot behavior is deemed malicious. These bots often perform tasks that create security risks for businesses and customers alike, such as accessing sensitive data without permission and preventing account access.  

Types of malicious bots that can impact businesses include:

• Botnets: The term "botnet" refers to a group of internet-connected devices, namely personal computers like laptops, that have been infected with a type of malware to leverage their shared computing power for shady activities, like sending spam.

• Distributed denial-of-service (DDoS) bots: These are applications that purposefully affect the availability of a server, service, or network by overwhelming the target with large volumes of traffic or requests that prevent legitimate users from accessing it. 

• File-sharing bots: These are designed to record frequent search terms on specific applications, search engines, or messaging platforms. They can distribute and manage the transfer of files within networks and over the internet, including malware and links to spam websites. 

• SMS pumping bots: SMS pumping bots take advantage of phone number input fields to send one-time passwords, app download links, and similar details to a range of numbers controlled by a specific mobile network operator. Fraudsters behind SMS pumping bots typically get a share of the generated revenue.

• Spambots: One of the oldest types of malicious bots, spambots crawl the internet for email addresses, create email lists, and deliver spam emails in large volumes. They can also use the data they collect to create fake accounts, post spam messages online, and send real users unwanted files. 

How are malicious bots created? 

All bots, including malicious ones, operate over a network interface. Most are connected to the internet and have an associated IP address, a numerical label that identifies the interface and indicates the source location. 

To create a malicious bot, bot developers need three things:

1. APIs

2. Application logic

3. Database

APIs are the building blocks of bots and most applications, and they allow two software components to communicate with each other. Bot developers write new application logic for APIs to define the specific actions, commands, and triggers they want malicious bots to take. 

From here, bots rely on databases to execute specific tasks. Many malicious bots, such as file-sharing bots, can expand databases over time. Others incorporate AI-powered deep learning techniques to continuously learn new words and phrases and simulate human conversation.

Business impact of malicious bot accounts

No company is immune to malicious bot accounts. From account compromise to revenue loss, the business impact of these bad bots can be debilitating. 

1. Account compromise and data theft 

During an account takeover (ATO), fraudsters and cybercriminals use malicious bots to rapidly cycle through account credentials, a tactic called credential stuffing. These bots can lock real customers out of their accounts and provide fraudsters with sensitive information for creating fake accounts.

Account takeovers compromise the validity of real customer accounts and decrease trust in your organization. Plus, they expose your company to considerable data theft. 

2. Degraded online services and customer churn 

Excessive malicious bot traffic can overwhelm your web servers, slowing down or even stopping service for real customers trying to access your website or app. 

While many attribute degraded online services to DDoS bots, this isn’t always the case. Just too many bots visiting your servers—from web crawlers to SMS pumping bots—can impair performance. Customers are more likely to churn if they frequently can’t access your website or app due to slow or unavailable service, especially if you’re a SaaS or telecommunications provider. 

3. Higher infrastructure and support costs

Malicious bots exploit flaws or gaps in the design and implementation of an API or application to improperly gain access to your accounts and user data. When this happens, infrastructure and support costs increase. 

4. Revenue loss  

Malicious bots and an influx of fake accounts can cause your business to lose revenue. The average amount organizations lost to cybercrime was $1.3 million in 2023, not including reputational damages.

How to detect a malicious bot 

Malicious bots have become increasingly sophisticated in recent years, but that doesn’t mean they’re impossible to detect. To identify bots, watch out for these telltale signs.

Abnormal page views, session durations, and bounce rates

If you experience a sudden, strange uptick in page views with sessions that are barely milliseconds long, bots are likely involved. Likewise, be wary of sudden and inexplicable spikes in your bounce rates. Malicious bots complete tasks quickly, so abnormally high bounce rates can be due to bots. 

Traffic spikes 

Traffic spikes, both in general and from countries where you usually do not sell or have customers, is a red flag. Frequent traffic from unusual locations usually involves bots. SMS pumping might also happen in countries where you do business, which makes it even harder to identify SIM swap fraud. The key thing to remember is that user authentication traffic is fairly regular and doesn’t have large spikes of traffic for verifications.

Incomplete and junk conversions 

Incomplete conversions are items like contact form fills and account sign-ups that have only been partially completed, such as providing a name and email address but not confirming either. Meanwhile, junk conversions refer to transactions that seem positive but have no true value. For instance, you may receive dozens of new email newsletter sign-ups, only to find out later that many of the emails don't work.

Incomplete and junk conversions are indicative of malicious bot activity, not human error. 

Suspicious accounts

Fake accounts are the primary indicator of malicious bot activity. To spot fake accounts, keep an eye out for multiple accounts that use similar usernames, email addresses, and other personal information but have no further activity post-sign-up.

Another sign of fake accounts is sign-ups that share the same IP address. Each device has its own IP address, so multiple accounts with wildly different names shouldn't share the same IP address. Moreover, accounts should not share the same user verification details. 

How to prevent bot attacks 

To prevent bots from wreaking havoc on your business, here are some ways to protect your organization. 

1. Deploy automatic SMS fraud detection

User verification tools like Twilio Verify can prevent SMS pumping fraud by bots. Verify is a fully managed API for multi-channel user verification that includes Fraud Guard to detect unusual fluctuations in SMS. 

Fraud Guard combines your customer behavioral data with knowledge of explicit fraud schemes to identify outliers in SMS activity and temporarily block user verification in suspicious situations, such as regions known for SMS pumping or areas your business has never sent SMS to before. It also identifies anomalous spikes in traffic and proactively blocks those texts.

2. Use mobile phone number intelligence

Twilio’s Lookup API provides businesses with an extra layer of security with real-time phone data. The Lookup API’s Line Type Intelligence is a type of phone number intelligence that allows you to identify virtual, temporary numbers which are easily disposable and easily procured by fraudsters. You can also identify VoIP numbers, which are often recognized as used for fraudulent purposes.

3. Implement user rate limiting

A bot may be able to make hundreds or thousands of requests in a short period of time! A real human would not send that many requests at once. Twilio Verify offers tools to prevent repeat requests over and over again. 

4. Enable user verification 

If a malicious bot manages to get past security checks like  reCAPTCHA and CAPTCHA,, two-step user verification can stop it. With tools like Twilio’s Silent Network Authentication (SNA), you can use direct carrier connections to verify a new phone number without requiring user input.

Twilio allows businesses to reduce fraud across channels with phone number verification that uses one API endpoint to validate users. So while bots can still spam request forms, they won't be able to create or access fake accounts. 

Learn more about creating a multi-factor authentication strategy for account recovery.

User verification and bot management with Twilio 

Bots are here, and they’re not leaving anytime soon. To ensure your business stays safe from harmful bots, check out our guide for buying versus building a user verification system and learn more about how to safeguard your business from malicious bots and fake accounts. Alternatively, if you’re looking for a hands-off approach to prevent fake account creation and validate users in real time, get in touch about building intelligent user verification with Twilio today.