When analyzing WAF logs, it’s essential to have a solid understanding of SQL injection attack techniques and patterns. SQL injection attacks are a type of cyberattack where malicious actors exploit vulnerabilities in a web application’s input fields to manipulate the underlying SQL database. Identifying SQL injection attacks requires vigilant monitoring and understanding of common attack patterns. Here are steps to help identify SQL injection attacks:
| Anomaly Patterns Look for anomalies in URL structures or query parameters. SQL injection attempts often involve injecting malicious strings, keywords, or symbols into input fields. Check for patterns that might indicate attackers attempting to manipulate SQL queries. Example: /products?category=' OR '1'='1' -- |
| SQL Keywords Examine the logs for any SQL keywords, operators, or fragments commonly used in SQL injection attacks. Keywords like “UNION,” “SELECT,” “OR,” and “AND” are often used to modify queries. Example: /search?query=UNION%20SELECT%20NULL,NULL,NULL-- |
| Tautology Attempts Search for tautology-based attacks where attackers might try to make the query always true, such as by appending ‘ OR ‘1’=’1′ to the input. Example: /login?username=admin' OR '1'='1'--&password=anything |
| Logical Operators Detect attempts to manipulate logical operators to change query behavior. For instance, attackers might use ‘ OR ‘1’=’1′ to bypass authentication. Example: /admin?user=' OR '1'='1'- |
| Error-Based Attacks Watch for error-based SQL injection attacks that might trigger database errors. Look for patterns indicating attackers attempting to extract database information through error messages. Example: /profile?id=1' AND 1=CONVERT(int, (SELECT @@version))-- |
| Time-Based Blind SQL Injection Examine for time delays introduced by attackers to exploit blind SQL injection vulnerabilities. Look for extended response times in the logs. Example: /search?query=anything' WAITFOR DELAY '0:0:5'-- |
| Out-of-Band Communication Look for evidence of attackers trying to establish out-of-band communication, such as making DNS requests or sending HTTP requests to exfiltrate data. |
| Blocked Requests Check for requests that were blocked by the WAF due to SQL injection detection rules. Analyze the payloads in these requests to understand the attack attempts. |
| Repeated Patterns Identify repeated patterns of requests with similar inputs that differ slightly. Attackers may iteratively test different payloads to identify vulnerabilities. |
| Common Injection Strings Search for known SQL injection attack strings in the logs. These strings are often used by attackers to test for vulnerabilities. |
