How To Avoid sql injections to existing code

Starx

This is a very vast field. However, There are few points I can give you

• Sanitize and filter every input you receive from the user.
• Handle every errors correctly. Do not even leave one possibility of an error being triggered
  ^{(This is a very important point and the main reason of most of the hacks)}
• If there were previous breaches, check the apache‘s log files to see where the injection happened. or where the hacking occur.
  1. There are mainly two types of logs file maintained in apache. access_log and error_log
  2. Once a breach occurs, make a backup of the logs and mitigate the problem, reviewing the logs.
• If a documentation is available for the system you are maintaining currently, then the vulnerability can be detected quicker.

Some helpful references

1. http://php.net/manual/en/security.database.sql-injection.php
2. http://simon.net.nz/articles/protecting-mysql-sql-injection-attacks-using-php/