The script builds an SQL query by concatenating hard-coded strings together with a string entered by the user: var Shipcity The following script shows a simple SQL injection. Subsequent text is ignored at execution time. Because the inserted command may have additional strings appended to it before it is executed, the malefactor terminates the injected string with a comment mark "-". The injection process works by prematurely terminating a text string and appending a new command. When the stored strings are subsequently concatenated into a dynamic SQL command, the malicious code is executed. A less direct attack injects malicious code into strings that are destined for storage in a table or as metadata. The primary form of SQL injection consists of direct insertion of code into user-input variables that are concatenated with SQL commands and executed. Even parameterized data can be manipulated by a skilled and determined attacker. Any procedure that constructs SQL statements should be reviewed for injection vulnerabilities because SQL Server will execute all syntactically valid queries that it receives. SQL injection is an attack in which malicious code is inserted into strings that are later passed to an instance of SQL Server for parsing and execution.
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