Is Your Website at Risk? Identifying Key Indicators of Brute Force, DDoS, and SQL Injection

Is your website at risk? If you suspect it is, it is essential to act swiftly to detect and respond to attacks. Brute force, DDoS (Distributed Denial of Service), and SQL injection are among the most common attack vectors, each posing unique threats:

• Brute force attacks overwhelm login mechanisms to gain unauthorized access.
• DDoS attacks flood your site with fake traffic, rendering it slow or unavailable.
• SQL injection attacks exploit database vulnerabilities to steal or manipulate sensitive data.

The first step to mitigating these threats is detecting their indicators early. This guide offers practical steps to determine whether your website is at risk by analyzing server logs, testing for vulnerabilities, and monitoring real-time activity. We’ll also demonstrate how to check if your website has experienced these attacks, providing sample commands, outputs, and interpretations.

Table of Contents

How to Detect if Your Website is at Risk from Common Attacks

Step 1: Detecting Brute Force Attacks

Brute force attacks aim to guess usernames and passwords through repeated login attempts. This can leave traces in your server’s authentication logs.

Command: Check for Failed Login Attempts

grep "failed" /var/log/auth.log  

Sample Output

Oct 15 09:12:01 server sshd[1057]: Failed password for invalid user admin from 192.168.1.5 port 54721 ssh2  
Oct 15 09:12:04 server sshd[1057]: Failed password for invalid user admin from 192.168.1.5 port 54721 ssh2  
Oct 15 09:12:07 server sshd[1057]: Failed password for invalid user admin from 192.168.1.5 port 54721 ssh2

Explanation

• Repeated login failures from the same IP suggest an ongoing brute force attack.
• The usernames attempted (e.g., admin) and source IP can offer clues about the attacker’s intent.

What to Look For:

• Multiple login failures in a short time from the same IP.
• Attempts using common usernames like admin, root, or test.

Step 2: Searching for SQL Injection Attempts

SQL injection attacks can leave malicious SQL queries in server logs, especially in the URL paths.

Command: Search for SQL Injection Indicators

grep -i "union select" /var/log/nginx/access.log  

Sample Output

192.168.1.5 - - [15/Oct/2024:10:02:31 +0000] "GET /report?id=1 UNION SELECT username, password FROM users -- HTTP/1.1" 200 1543  

Explanation

• The UNION SELECT keyword is a typical SQL injection attempt to retrieve data from your database.
• The HTTP status code 200 means the query succeeded, indicating a potential vulnerability.

What to Look For:

• SQL keywords like UNION, SELECT, or OR 1=1 in logs.
• Requests containing database tables or field names (e.g., username, password).

Step 3: Confirming SQL Injection Vulnerability with SQLmap

SQLmap can simulate a SQL injection attack to check if your site is vulnerable.

Command: Use SQLmap on a Target URL

sqlmap -u "http://gbv-report-site.com/report?id=1" --dbs  

Sample Output

[INFO] testing 'AND boolean-based blind'  
[INFO] the target URL appears to be vulnerable.  
[INFO] available databases [2]:  
[*] gbv_report  
[*] mysql  

Explanation

• The target URL appears to be vulnerable confirms the presence of an SQL injection vulnerability.
• SQLmap lists available databases, indicating the extent of the risk if left unresolved.

What to Look For:

• Any indication of a vulnerable parameter.
• Databases containing sensitive information listed in the output.

Step 4: Monitoring Logs for Real-Time Attacks

If your website is at risk of ongoing attacks, monitoring your logs in real-time helps you respond quickly.

Command: Monitor Nginx Logs for Suspicious Activity

tail -f /var/log/nginx/access.log | grep -E 'login|select|union'  

Sample Output

192.168.1.5 - - [15/Oct/2024:10:10:12 +0000] "POST /login HTTP/1.1" 401 423  
203.0.113.42 - - [15/Oct/2024:10:11:45 +0000] "GET /report?id=1 UNION SELECT username, password -- HTTP/1.1" 200 1543  

Explanation

• POST requests to /login with a 401 Unauthorized status indicate repeated failed login attempts.
• GET requests containing SQL queries in the URL suggest an SQL injection attempt.

What to Look For:

• High-frequency login attempts from the same IP.
• Suspicious SQL queries in URL paths or parameters.

Step 5: Identifying DDoS Attacks

DDoS attacks overwhelm your website with excessive requests from multiple IPs, slowing or crashing your server.

Command: Monitor Traffic for DDoS Indicators

netstat -an | grep ':80' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -nr  

Sample Output

300 203.0.113.42  
250 198.51.100.10  
180 192.168.1.5 

Copy code 

Explanation

• Netstat shows the number of connections to port 80 (HTTP) from each IP.
• If you see hundreds of connections from individual IPs, it’s likely a DDoS attack.

What to Look For:

• High connection counts from the same IP.
• Multiple IPs attempting connections at the same time.

Conclusion

If your website is at risk, these steps will help you identify signs of brute force, DDoS, and SQL injection attacks. Reviewing logs, running SQLmap tests, and monitoring real-time traffic are essential practices to detect and respond to these threats effectively.

Remember:

• For brute force attacks, watch for repeated login failures from the same IP.
• For SQL injection, inspect logs for malicious SQL queries and use SQLmap to confirm vulnerabilities.
• For DDoS, monitor traffic to detect unusually high connection counts from multiple IPs.

If any of these attacks are detected, block the offending IPs immediately, apply security patches, and enable Web Application Firewalls (WAF) to prevent further breaches.