Cheat Sheet

My Tricks

  • Use SELECT * FROM Users\G instead of SELECT * FROM Users; to get nicer formatting.

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:

Conditional Errors

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

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

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:

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:

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:

Reference

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