Tests APIs for injection vulnerabilities including SQL injection, NoSQL injection, OS command injection, LDAP injection, and Server-Side Request Forgery (SSRF) through API parameters, headers, and request bodies. The tester crafts malicious payloads targeting different backend technologies and injection contexts to extract data, execute commands, or access internal services. Maps to OWASP API8:2023 Security Misconfiguration and API7:2023 SSRF. Activates for requests involving API injection testing, SQLi in APIs, NoSQL injection, SSRF testing, or API input validation assessment.
Tests APIs for injection vulnerabilities including SQL injection, NoSQL injection, OS command injection, LDAP injection, and Server-Side Request Forgery (SSRF) through API parameters, headers, and request bodies. The tester crafts malicious payloads targeting different backend technologies and injection contexts to extract data, execute commands, or access internal services. Maps to OWASP API8:2023 Security Misconfiguration and API7:2023 SSRF. Activates for requests involving API injection testing, SQLi in APIs, NoSQL injection, SSRF testing, or API input validation assessment.
Testing API endpoints that accept user input for database queries, system commands, or external requests
Assessing APIs that interact with SQL databases, NoSQL stores (MongoDB, Redis), LDAP directories, or external URLs
Evaluating input validation and parameterized query usage across all API endpoints
Testing for SSRF where API parameters accept URLs or hostnames that trigger server-side requests
Identifying injection points in headers, path parameters, query strings, and JSON/XML request bodies
Do not use without written authorization. Injection testing can modify or destroy data and compromise backend systems.
Prerequisites
Written authorization specifying target API and backend systems in scope
Python 3.10+ with requests library
SQLMap for automated SQL injection detection and exploitation
Burp Suite Professional with Active Scan capabilities
Knowledge of the backend database technology (MySQL, PostgreSQL, MongoDB, Redis)
Isolated test environment to avoid production data corruption
Legal Notice: This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.
Inserting SQL code into API parameters that are concatenated into database queries, enabling data extraction or modification
NoSQL Injection
Injecting NoSQL operators ($ne, $gt, $regex) into MongoDB queries or manipulating Redis/Elasticsearch queries through API parameters
SSRF
Server-Side Request Forgery (OWASP API7:2023) - forcing the server to make HTTP requests to attacker-specified destinations including internal services
Command Injection
Injecting OS commands through API parameters that are passed to shell execution functions (exec, system, popen)
Parameterized Queries
Using prepared statements with bound parameters to prevent SQL injection by separating code from data
Input Validation
Server-side verification that user input conforms to expected format, type, length, and character set before processing
Tools & Systems
SQLMap: Automated SQL injection detection and exploitation tool supporting all major database types
Burp Suite Professional: Active scanner with injection detection for SQL, NoSQL, SSRF, and command injection
NoSQLMap: Automated NoSQL injection detection and exploitation tool focused on MongoDB
SSRFmap: SSRF detection and exploitation framework with cloud metadata extraction modules
Commix: Automated OS command injection detection and exploitation tool
Common Scenarios
Scenario: E-Commerce API Injection Assessment
Context: An e-commerce API uses PostgreSQL for the product catalog, MongoDB for user sessions, and accepts webhook URLs for order notifications. The API is built with Node.js/Express.
Approach:
Test product search endpoint GET /api/v1/products?search=test with SQL payloads - discover error-based SQLi revealing PostgreSQL 14 backend
Exploit union-based SQLi to extract all table names, then dump user credentials from the users table
Test login endpoint with NoSQL operators - {"username":{"$ne":""},"password":{"$ne":""}} bypasses authentication
Test webhook URL endpoint for SSRF - POST /api/v1/webhooks {"url":"http://169.254.169.254/latest/meta-data/"} returns AWS instance metadata
Extract AWS IAM role credentials via SSRF, gaining access to S3 buckets containing customer data
Test file export endpoint for command injection - GET /api/v1/export?filename=report;cat /etc/passwd returns passwd file contents
Pitfalls:
Only testing SQL injection when the backend uses multiple data stores (SQL, NoSQL, Redis, Elasticsearch)
Missing injection points in HTTP headers (User-Agent, Referer, X-Forwarded-For) that may be logged to SQL databases
Not testing SSRF bypass techniques when the initial payload is blocked by URL validation
Assuming JSON API bodies are safe from SQL injection (JSON values are still concatenated into queries)
Not testing time-based injection when error messages are suppressed
Output Format
## Finding: SQL Injection in Product Search API Enables Full Database Access
**ID**: API-INJ-001
**Severity**: Critical (CVSS 9.8)
**OWASP API**: API8:2023 - Security Misconfiguration / Injection
**Affected Endpoints**:
- GET /api/v1/products?search= (SQL injection)
- POST /api/v1/auth/login (NoSQL injection)
- POST /api/v1/webhooks (SSRF)
**Description**:
The product search API concatenates user input directly into a PostgreSQL
query without parameterization. An attacker can extract all database
contents including user credentials, payment information, and admin
secrets. Additionally, the login endpoint is vulnerable to MongoDB
NoSQL operator injection, and the webhook endpoint allows SSRF to
internal services and cloud metadata.
**Impact**:
- Full database read/write access via SQL injection
- Authentication bypass via NoSQL operator injection
- AWS IAM credential theft via SSRF to instance metadata
- Potential remote code execution via SQL injection stacked queries
**Remediation**:
1. Use parameterized queries for all database operations
2. Validate and sanitize NoSQL operator characters in JSON input
3. Implement URL allowlisting for webhook and callback URLs
4. Block access to cloud metadata endpoints (169.254.169.254) from application servers
5. Use an ORM with parameterized queries and disable raw query methods
6. Implement WAF rules for common injection patterns as defense in depth
