What is a Botnet? How to Detect & Prevent Attacks

A botnet (or “robot network”) is a collection of networked devices infected with malware and hijacked to perpetrate large-scale scams and data breaches.

In this blog, we will discuss how a botnet works, what they are used to accomplish, and how to take them down.

How A Botnet Works

Botnet infections occur when a vulnerability – such as a user’s behavior – is exploited. Once a device is infected, the malware takes control of the machine and quickly spreads across the network, infecting potentially thousands of other machines. A botnet attack can be executed with minimal effort and little cost, making it an increasingly popular threat vector. 

A botnet is controlled remotely by a threat actor – or “bot-herder” – using malware. Once scale has been achieved, the bot-herder will take remote control of the botnet and assume administrator rights. From that point, they can manage file permissions, gather personal data, monitor user activity, scan for vulnerabilities, and install software that triggers secondary attacks.

Botnets are sneaky. In fact, without the proper monitoring technology, security teams are typically unaware that systems have been infected.

Why Botnets Are So Damaging

Having an army of bots infect and control your network is like having a hacker living inside your IT infrastructure ready to initiate nefarious activity at any time. For this reason, botnet infections cannot be ignored.

Indeed, a Bitsight study found a direct link between botnets and significant, publicly disclosed data breaches. When we analyzed the security ratings of more than 6,000 companies, we found those with a botnet grade of “B” or lower are twice as likely to experience a botnet attack that compromises personally identifiable information and leads to financial and reputation damage.

Disrupting Botnets

Bitsight has a long history of observing and understanding the inner workings of botnets and has worked with law enforcement and private sector organizations on their disruption activities. For example, in 2017, we collaborated with Microsoft’s Digital Crimes Unit (DCU) to understand and disrupt a massive criminal botnet known as the Necurs malware.

We initially discovered that Necurs had around one million infected systems, but it was spreading rapidly. By 2020, Necurs had infected nine million computers globally. That same year, with help from Bitsight’s insights, Microsoft took steps to disrupt all Necurs botnets and mitigate impacted systems.

How To Prevent Botnet Attacks

Since botnet infections can lay hidden for some time, you first need to understand if your organization is already infected. 
In a similar way to how a doctor might order diagnostics to identify underlying health problems, Bitsight Security Ratings can be used to assess the cyber health of your digital environment.   

Security ratings use expansive data-scanning technology to provide an outside-in view of your organization’s security posture, including compromised systems, and the risk of a public breach. Executives, board members, and security and risk teams can use your rating to understand cyber performance and make informed security decisions.

Because botnets are continually evolving, keep a finger on the pulse of your security performance by continuously and automatically monitoring your environment for emerging risks. With Bitsight, you’ll receive near real-time alerts the moment a potential system vulnerability or infection is detected, so you can take quick action to remediate risk.  

Once a botnet takes over your digital infrastructure, they can be very hard to stop. Take steps now to ensure you have a plan to detect and prevent attacks.