DEV Community

Hawkinsdev
Hawkinsdev

Posted on

How Hackers Scan the Internet in 5 Minutes

#hacker #cybersecurity #safeline

If you expose a server to the public internet, there's a good chance someone will scan it within minutes.

It doesn't matter if you're running a personal blog, a startup API, or a cloud server. The internet is constantly being scanned by automated tools looking for open ports, vulnerable services, and misconfigured systems.

In this article, we'll break down:

  • How attackers scan the entire internet in minutes
  • The tools commonly used by attackers
  • What happens after a vulnerable service is discovered
  • Practical defenses you can deploy today

The Reality: The Internet Is Constantly Being Scanned

Many developers assume attackers manually target specific systems. In reality, most attacks begin with mass automated scanning.

Attackers use high-speed tools that can probe millions of IP addresses per minute.

Typical scanning workflow:

1. Scan the internet for open ports
2. Identify services and versions
3. Look for known vulnerabilities
4. Attempt automated exploitation
Enter fullscreen mode Exit fullscreen mode

This entire process can run continuously across botnets and cloud servers.

Step 1: High-Speed Internet Scanning with Masscan

One of the fastest internet scanners available today is Masscan.

Masscan is capable of scanning the entire IPv4 internet in minutes by sending packets asynchronously at extremely high rates.

Example command:

masscan 0.0.0.0/0 -p80,443 --rate 1000000
Enter fullscreen mode Exit fullscreen mode

What this does:

Target: entire IPv4 space
Ports: 80 and 443
Speed: 1,000,000 packets per second
Enter fullscreen mode Exit fullscreen mode

Within minutes, attackers can discover thousands of servers exposing web services.

Masscan focuses only on speed and port discovery, not detailed analysis.

Step 2: Service Fingerprinting with Nmap

After identifying open ports, attackers often switch to Nmap for deeper inspection.

Nmap provides detailed information about services running on a host.

Example command:

nmap -sV -p80,443 192.168.1.10
Enter fullscreen mode Exit fullscreen mode

This reveals:

open ports
service type
software version
operating system hints
Enter fullscreen mode Exit fullscreen mode

Example output:

80/tcp open  http     nginx 1.18.0
443/tcp open https    Apache 2.4.52
Enter fullscreen mode Exit fullscreen mode

This information helps attackers determine which vulnerabilities may exist.

Step 3: Automated Vulnerability Scanning

Once services are identified, attackers often launch automated exploit scanners.

These scanners test for known vulnerabilities such as:

SQL injection
Remote code execution
Weak admin panels
Exposed debug endpoints
Misconfigured cloud storage
Enter fullscreen mode Exit fullscreen mode

Example scanning tools:

  • vulnerability scanners
  • exploit frameworks
  • botnet scanners

A typical automated scan may test hundreds of payloads against a single endpoint.

For example:

/login
/admin
/phpmyadmin
/.env
/api/debug
Enter fullscreen mode Exit fullscreen mode

Attackers are simply looking for anything that responds differently.

What Happens When a Vulnerability Is Found

Once a vulnerable service is detected, the attack may escalate quickly.

Typical next steps include:

1. Exploit vulnerability
2. Upload web shell
3. Deploy malware or crypto miner
4. Move laterally in the network
Enter fullscreen mode Exit fullscreen mode

Many compromises happen within minutes after exposure.

This is why newly deployed servers often receive attack traffic almost immediately.

How to Defend Against Internet-Wide Scanning

Because scanning is inevitable, the goal is reducing attack surface and blocking automated traffic.

Here are several practical defenses.

1. Firewall Rules

A properly configured firewall can prevent unnecessary exposure.

For example, instead of exposing SSH to the entire internet:

Allow SSH only from trusted IPs
Block unused ports
Drop suspicious traffic
Enter fullscreen mode Exit fullscreen mode

Example rule concept:

Allow:
  22/tcp from office IP

Deny:
  22/tcp from all others
Enter fullscreen mode Exit fullscreen mode

This dramatically reduces brute-force attacks.

2. Web Application Firewall (WAF)

Many internet scanners target web applications.

A Web Application Firewall analyzes HTTP traffic and blocks malicious patterns such as:

SQL injection attempts
scanner signatures
exploit payloads
path probing attacks
Enter fullscreen mode Exit fullscreen mode

Tools like SafeLine WAF can automatically detect abnormal request patterns and stop automated scanners before they reach your application.

3. Rate Limiting

Attack scanners typically send requests very quickly.

Rate limiting can detect and block suspicious behavior.

Example protection:

limit 50 requests per minute per IP
block repeated failed login attempts
throttle suspicious endpoints
Enter fullscreen mode Exit fullscreen mode

This prevents automated tools from rapidly probing your system.

4. Reduce Your Attack Surface

The safest service is the one not exposed to the internet.

Best practices:

disable unused services
close unnecessary ports
hide admin interfaces behind VPN
use private networks for internal services
Enter fullscreen mode Exit fullscreen mode

Many real-world breaches happen simply because something was exposed accidentally.

Final Thoughts

The internet is not a quiet place.

Within minutes of connecting a server to the public network, it will likely receive:

port scans
bot probes
vulnerability scans
credential attacks
Enter fullscreen mode Exit fullscreen mode

Attackers don't need to manually search for targets anymore — automation does it for them.

The key defenses are simple but powerful:

firewalls
WAF protection
rate limiting
reduced attack surface
Enter fullscreen mode Exit fullscreen mode

If your services are exposed to the internet, assume that they are already being scanned right now.

Safeline is an open‑source, self‑hosted web application firewall and reverse proxy that focuses on semantic, AI‑driven detection, broad attack coverage, and built‑in bot and DDoS protections.

SafeLine Website:
https://safepoint.cloud/landing/safeline
Live Demo:
https://demo.waf.chaitin.com:9443/statistics
Discord:
https://discord.gg/dy3JT7dkmY
Docs:
https://docs.waf.chaitin.com/en/home
Github:
https://github.com/chaitin/SafeLine

Top comments (0)