Red Flags That Your Website Is Already Being Probed by Attackers

I often remind clients that cyberattacks rarely start with exploitation. They start with reconnaissance. Before launching a full-blown attack, adversaries quietly test your defenses, scan for weaknesses, and map your environment. By the time an exploit hits, your website has likely been probed dozens of times.

Reconnaissance, Tactic TA0043 — Enterprise (MITRE ATT&CK®)

The good news?

If you know what to look for, the signs are often right there, hidden in your logs and traffic patterns. Here are the most common red flags that your website may already be under reconnaissance.

Unusual Traffic Patterns

Attackers rarely behave like normal users. Watch for sudden spikes in requests from unfamiliar IPs or countries where you don’t operate.

Check with tools like Cloudflare Analytics, Google Cloud Armor Logs, or AWS WAF logging to visualize traffic anomalies.

If your access logs show sequential requests hitting paths like:

/admin
/phpmyadmin
/wp-login.php
/robots.txt
/.env

That’s not a coincidence, it’s mapping. High volumes of 404 or 403 errors are also telltale signs of automated discovery tools trying to locate sensitive files or hidden endpoints.

Common scanning tools: Nikto, Gobuster, dirb

Check: Review access logs weekly and look for repetitive access to uncommon URLs or specific file types (like .bak, .old, or .git).

Strange Log Entries

Your web server logs are your early warning system. You can analyze logs manually or through platforms like ELK Stack or Graylog. If you see patterns like:

• Query strings with odd symbols (?id=1', UNION SELECT, OR 1=1)
• Directory traversal attempts (../../etc/passwd)
• Requests from suspicious user-agents (sqlmap, curl, empty headers)

…it’s almost certain your site is being probed.

Sqlmap is an open-source SQL injection tool often used in automated probing.

Automated vulnerability scanners and opportunistic attackers often leave behind these recognizable footprints. Even if the attempts failed, they reveal that your perimeter is being actively tested.

Frequent 500 or 400 Errors

Repeated 500 Internal Server Errors triggered by external requests are a major red flag. These errors usually occur when someone sends malformed or unexpected data, intentionally trying to crash or fuzz your backend. Read more about fuzzing: OWASP Fuzzing Overview.

A burst of random 400-series or 500-series errors isn’t just bad traffic. It’s reconnaissance in action. Someone is learning how your application breaks.

Access Attempts to Sensitive Files

Attackers routinely attempt to retrieve internal configuration files, like:

• .env ,.htaccess ,.git/config ,composer.json or package.json

These files often contain credentials or environment details. Repeated requests for such resources should be treated as serious intrusion attempts.

My assessments frequently uncover exposed configuration data that was never meant to be public, a common but dangerous oversight.

Failed Login Bursts or Suspicious Authentication Activity

If your logs show multiple failed login attempts in a short time, especially from different countries or IP ranges, someone’s testing your authentication system.

Other signs include:

• Logins from unknown devices using admin or test accounts
• Brute-force patterns (e.g., 100+ failed attempts per minute)
• Attempts with default usernames: “admin”, “root”, “test”, “user”

Implementing rate-limiting and MFA can drastically reduce your exposure here.

Irregular API Activity

APIs are often the weakest point of modern applications. Unrecognized API calls, repeated unauthorized token usage, or spikes in failed requests indicate that attackers are exploring your backend endpoints.

If your APIs aren’t logging properly, you could be blind to this entire category of probing.

Learn API hardening best practices: OWASP API Security Top 10

Your Domain Appears in Public Threat Feeds

Many reconnaissance tools share or publish lists of scanned domains. If your domain appears in public scan datasets or dark web forums, it’s a strong indicator that it’s already on someone’s radar.

I monitor threat intelligence feeds and attack surface datasets to detect when our clients’ domains show up in these collections, often before a breach attempt even occurs.

You can check for mentions using Shodan, Censys, or SecurityTrails

Strengthening Your Defenses

Detecting probing activity early is only the first step. The real goal is to understand why it’s happening and how to close the gaps attackers are testing.

Start by:

• Reviewing your exposed assets and public-facing endpoints.
• Conducting a thorough manual assessment (not just automated scans).
• Validating your application logic, authentication flow, and access controls.
• Setting up continuous monitoring for reconnaissance behavior.

If you don’t have the internal resources or time to perform these checks, consider collaborating with experienced offensive security professionals who can replicate real attacker techniques and provide actionable guidance.

Conclusion

Thanks for taking the time to read this. Cybersecurity awareness grows when professionals share knowledge, and every small improvement in visibility can prevent a major incident.