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A classification of SQL injection attacking vector as of 2010. In computing, SQL injection is a code injection technique used to attack data-driven applications, in which malicious SQL statements are inserted into an entry field for execution (e.g. to dump the database contents to the attacker).
Code injection is a computer security exploit where a program fails to correctly process external data, such as user input, causing it to interpret the data as executable commands. An attacker using this method "injects" code into the program while it is running.
It was introduced to help newcomers write functioning SQL commands without requiring manual escaping. It was later described as intended to prevent inexperienced developers from writing code that was vulnerable to SQL injection attacks. This feature was officially deprecated as of PHP 5.3.0 and removed in PHP 5.4, due to security concerns. [1]
If any of these variables is used to execute dangerous commands (such as direct commands to a SQL database or the host computer operating system), the taint checker warns that the program is using a potentially dangerous tainted variable. The computer programmer can then redesign the program to erect a safe wall around the dangerous input.
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
Stored procedure parameters will be treated as data even if an attacker inserts SQL commands. Also, some DBMS will check the parameter's type. However, a stored procedure that in turn generates dynamic SQL using the input is still vulnerable to SQL injections unless proper precautions are taken.
Major DBMSs, including SQLite, [5] MySQL, [6] Oracle, [7] IBM Db2, [8] Microsoft SQL Server [9] and PostgreSQL [10] support prepared statements. Prepared statements are normally executed through a non-SQL binary protocol for efficiency and protection from SQL injection, but with some DBMSs such as MySQL prepared statements are also available using a SQL syntax for debugging purposes.
Injection exploits are computer exploits that use some input or data entry feature to introduce some kind of data or code that subverts the intended operation of the system. Usually these exploits exploit vulnerabilities resulting from insufficient data validation on input and so forth.