Detecting SQL Injection Vulnerabilities

Overview

Scan application source code for SQL injection vulnerabilities (CWE-89, OWASP A03:2021) by tracing user input from entry points through data flows into database query construction. Detect string concatenation, format string interpolation, and inadequate parameterization across raw SQL, ORM raw query methods, stored procedure calls, and dynamic query builders.

Prerequisites

• Application source code accessible in ${CLAUDE_SKILL_DIR}/
• Database query files, ORM models, and repository/DAO layers available
• Framework and language identified (Django, Rails, Express, Spring, Laravel, ASP.NET, Go, etc.)
• Database type known (MySQL, PostgreSQL, SQLite, MSSQL, Oracle) for syntax-specific detection
• Write permissions for reports in ${CLAUDE_SKILL_DIR}/security-reports/

Instructions

1. Discover database interaction code: search for SQL keywords (SELECT, INSERT, UPDATE, DELETE, EXEC) and ORM raw query methods (raw(), execute(), createNativeQuery(), $wpdb->query()) across all source files.
2. Identify input surfaces: map all user-controllable data entry points -- HTTP parameters, request bodies, URL path segments, headers, cookies, file uploads, and WebSocket messages.
3. Trace data flows: follow each input surface through the code to determine whether user data reaches a SQL query. Flag any path where input is not passed through parameterized query binding.
4. Detect vulnerable patterns:
   • String concatenation: "SELECT * FROM users WHERE id=" + userId
   • f-string/format interpolation: f"SELECT * FROM users WHERE name='{name}'"
   • Template literals: `SELECT * FROM users WHERE id=${req.params.id}`
   • ORM raw queries without bindings: Model.objects.raw("SELECT * FROM t WHERE x='" + val + "'")
5. Classify each finding: assign CVSS 3.1 score, identify attack type (classic injection, blind boolean/time-based, UNION-based exfiltration, second-order/stored injection), and document exploitability (authentication required, network access).
6. Assess impact per finding: determine data exposure scope (authentication bypass, data exfiltration, data modification, OS command execution via xp_cmdshell or LOAD_FILE()).
7. Generate remediation code: provide parameterized equivalents for each vulnerable query. Use framework-idiomatic patterns -- %s placeholders for Python DB-API, ? for Node.js, $1 for PostgreSQL, named parameters for Spring JPA.
8. Recommend defense-in-depth measures: input validation (allowlists over denylists), stored procedures with parameterized calls, least-privilege database accounts, WAF rules, and ORM-only data access policies.
9. Produce the vulnerability report at ${CLAUDE_SKILL_DIR}/security-reports/sqli-scan-YYYYMMDD.md with per-finding severity, CWE-89 mapping, file path and line number, vulnerable code snippet, attack vector demonstration, and remediated code.

See ${CLAUDE_SKILL_DIR}/references/implementation.md for the detection pattern library. See ${CLAUDE_SKILL_DIR}/references/critical-findings.md for example vulnerability write-ups with attack demonstrations.

Output

• Vulnerability Report: ${CLAUDE_SKILL_DIR}/security-reports/sqli-scan-YYYYMMDD.md with all findings classified by severity
• Finding Details: per-finding file path, line number, vulnerable code, attack vector, CVSS score, and remediation code
• Remediation Summary: parameterized query replacements grouped by language/framework
• Defense Recommendations: input validation rules, database privilege changes, and WAF configuration

Error Handling

Error	Cause	Solution
Unknown ORM or database framework	Custom or uncommon data access library	Apply generic SQL injection pattern detection; note limited framework-specific guidance
Cannot analyze compiled/minified code	Production bundles or bytecode instead of source	Request unminified source; document reduced detection accuracy
False positive on sanitized input	Proper sanitization exists but not recognized	Trace sanitization implementation manually; whitelist verified-safe patterns
Complex dynamic query builder logic	Multi-step query construction across modules	Trace full data flow manually; flag for manual security review
Cannot analyze stored procedure definitions	SQL source files not available in ${CLAUDE_SKILL_DIR}/	Request .sql files or database schema exports; focus on application-layer code

Examples

• "Scan the codebase for SQL injection risks in dynamic query construction, focusing on controllers and API handlers."
• "Review these query snippets and propose parameterized equivalents with unit tests validating the fix."
• "Detect second-order SQL injection in the user profile update flow where stored data is later used in admin queries."

Resources

• OWASP SQL Injection Prevention Cheat Sheet: https://cheatsheetseries.owasp.org/cheatsheets/SQL_Injection_Prevention_Cheat_Sheet.html
• CWE-89 Improper Neutralization of SQL Syntax: https://cwe.mitre.org/data/definitions/89.html
• OWASP A03:2021 Injection: https://owasp.org/Top10/A03_2021-Injection/
• CAPEC-66 SQL Injection: https://capec.mitre.org/data/definitions/66.html
• ${CLAUDE_SKILL_DIR}/references/critical-findings.md -- example vulnerability write-ups with attack vectors
• ${CLAUDE_SKILL_DIR}/references/errors.md -- full error handling reference
• ${CLAUDE_SKILL_DIR}/references/examples.md -- additional usage examples
• https://intentsolutions.io