SQL injection principles and examples

• Introduction

With the development of B/s pattern application development, more and more programmers use this model to write applications. However, due to the lack of entry threshold in this industry, the level and experience of programmers is also uneven, a large part of the programmer in writing code, the user does not judge the legality of input data, so that the application has a security risk. The user can submit a database query code, according to the results returned by the program, to obtain some of the data he wants to know, this is called SQL injection, that is, SQL injection.

SQL injection is accessed from the normal WWW port, and the surface seems to be no different from the General Web page access, so the current firewall in the market does not alert SQL injection, if the administrator does not view the IIS log habits, may be invaded for a long time will not be detected. However, the approach of SQL injection is quite flexible, and there are many unexpected situations when injected. Can analyze according to the specific situation, constructs the ingenious SQL statement, thus obtains the desired data successfully, is the master and "rookie" the fundamental difference.

According to national conditions, the domestic website with asp+access or SQL Server accounted for more than 70%, php+mysq accounted for 20%, the other less than 10%. In this article, we from the sub-entry, advanced to high-level to explain the ASP injection methods and techniques, PHP injection of the article by the NB Alliance, another friend Zwell wrote, hoping to be useful to security workers and programmers. Learn about ASP injection friends also do not skip the introductory article, because some people to inject the basic judgment method still has the misunderstanding. Are you ready for the job? Lets Go ...

• Introductory article

If you haven't tried SQL injection before, the first step is to get the IE menu + tools = + Internet options + advanced + Show friendly HTTP error message before the tick is removed. Otherwise, IE will only appear as an HTTP 500 server error, and no more prompts will be available, regardless of what error the server returns.

The first section, SQL injection principle

SQL injection principles and examples