Long before your server gets attacked, it may already have become part of the attack. That is exactly what a botnet is: an army of thousands of compromised, remotely controlled devices operating without their owners' knowledge. It contains home computers, cameras, routers and — far too often — insufficiently hardened VDS instances. This guide explains what a botnet is, how a server ends up joining one, which symptoms give it away, and how to clean it up so it never happens again.
The word botnet comes from combining "robot" and "network". It describes a collection of devices infected with malicious software and controlled through a central command structure. Each compromised device is called a bot or a zombie. These machines keep doing their normal jobs: your site loads, your game server runs, your emails go out. Staying unnoticed is the core design goal of a botnet, because a bot that gets noticed gets cleaned and drops out of the network.
What makes botnets dangerous is not the power of individual devices but their sum. A single home router cannot generate meaningful traffic. But when hundreds of thousands of devices point at the same target simultaneously, the result is a capacity no single attacker could ever assemble alone. The vast majority of modern DDoS attacks work on exactly this principle.
The attacker first needs to take over devices. Automated scanners handle this: IP blocks across the internet are continuously swept, open ports are identified, and known vulnerabilities or weak passwords are tried. There is no such thing as a server "too small to be interesting" — scans do not pick targets, they walk address ranges. It is entirely normal for a freshly deployed server to receive its first SSH login attempts within minutes.
An infected device connects to a command server under the attacker's control and waits for instructions. Older botnets used IRC channels; today it is common to see variants that communicate over HTTPS so the traffic looks like ordinary web browsing, or peer-to-peer designs with no central point at all. This makes detection harder, because outbound traffic looks unremarkable at first glance.
Most botnets are not used by their operators directly — they are rented out, sold in hourly or daily packages on underground markets. This means that once your server is compromised, what it will be used for is not decided in advance: it may send spam today and join a DDoS attack tomorrow.
Botnet software tries to hide, but it cannot operate without leaving traces. Watch for these:
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top.crontab -l that you never added are the most common persistence mechanism./etc/passwd and ~/.ssh/authorized_keys.ss -tupn reveals persistent connections to IP addresses you do not recognise.Work through this in order — do not start deleting things in a panic:
Most of the protection comes from disciplined fundamentals rather than exotic tooling:
For a detailed, actionable version of these steps, see our guide on server security for a new VDS setup.
Part of server security is your responsibility, part of it belongs to the provider. A DDoS-protected network layer both filters incoming attacks and makes abnormal outbound traffic easier to spot. A local point of presence matters too, for latency and for response speed: being in the same time zone as support when something goes wrong saves hours.
At Nubitro, services run in the Istanbul location on AMD Ryzen 9 9950X processors with DDR5 RAM and NVMe M2 SSD storage, on a DDoS-protected network. You can review current configurations on the Turkey location VDS/VPS page, or look at dedicated servers for workloads that need isolated hardware. For game projects specifically, see the MTA server options.
As the owner and administrator of the server, you are held accountable for the traffic leaving your IP address. Lack of intent is a mitigating factor, but your provider may still suspend the service or you may receive a formal notice. This is why responding quickly to abuse reports matters.
No. On the server side, most malware is compiled in ways signature-based scanning will miss, or it runs using legitimate system tools. Antivirus is a useful layer, but it does not replace configuration hardening, patch discipline and monitoring.
Technically possible, practically not recommended. You cannot know with certainty which persistence mechanisms the attacker left behind. Cleanup may be worth attempting on a non-critical system; on anything holding data or customers, a fresh install is the only safe path.
Yes. The operating system is not the deciding factor — configuration and patch level are. On Windows, leaving RDP exposed to the internet with default settings is the most common entry point.
Two reasons: third-party scripts and mods are loaded without review, and game servers are high-bandwidth machines that stay online continuously, which makes them valuable to an attacker. Verifying the source of a third-party script before installing it eliminates most of this risk class.
Start with three commands: top for unexpected CPU consumption, ss -tupn for outbound connections you do not recognise, and crontab -l plus /etc/cron.d for scheduled tasks you never added. On top of that, check your IP against a blacklist lookup service.
A botnet is a network of compromised devices that becomes rentable attack capacity. Your server can join one because of a weak password, an unpatched application, an exposed management service, or an untrusted script. The symptoms are usually unexplained CPU usage, rising outbound traffic, a blacklisted IP, and cron jobs you did not create. If you suspect a compromise, the correct order is: isolate, investigate, rotate credentials, rebuild, restore from a verified backup. On the prevention side, key-based SSH, a strict firewall, regular updates, monitoring and off-server backups are the five fundamentals.
If you want infrastructure designed with security as a priority, share your current configuration with our support team, or start by reviewing the Turkey location VDS options.