Shulou(Shulou.com)05/31 Report--

This article mainly introduces "what is the essence of SQL injection attack". In daily operation, I believe that many people have doubts about the nature of SQL injection attack. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts about "what is the nature of SQL injection attack". Next, please follow the editor to study!

As the Microsoft boss said, it is caused by improper coding by developers of website programs, not only ASP, ASP.NET, but also JSP, PHP and other technologies, and affected not only Access and SQL Server databases, but also other relational databases such as Oracle and MySql, which have nothing to do with Microsoft. In fact, this problem exists not only in the system or website based on the Bhand S architecture, but also in the system based on the Camp S architecture, but it is impossible to have such an extensive influence as the Bhand S system because of the characteristics of the Camp S architecture. So why do we say that this problem is caused by improper coding by developers? let's analyze it in detail below.

First, let's take a look at these two SQL query statements

Statement 1:select * from news where newstype=1

Statement 2:select * from news where newstype=1;drop table news

Sentence 3:select * from news where newstype=' Social News'

Statement 4:select * from news where newstype=' Social News'; drop table news--'

We all know that the role of statement 1 is to query all records in the news table where the value of the newstype field is equal to 1, in which the type of newstype field is a numerical type, such as Int, SmaillInt, TinyInt, Float, and so on; statement 2 is actually two statements, the first and statement 1 have the same effect, and the second is to delete the news table in the database. The functions of statement 3 and statement 4 are basically the same as those of statement 1 and statement 2, except that the newstype fields in statements 3 and 4 are character-based, such as char, varchar, nvarchar, text and so on.

Whether in ASP or ASP.NET or JSP or PHP, we usually use the method of "select * from news where newstype=" + v_newstype to construct statement 1, or "select * from news where newstype='" + v_newstype + "'" to construct statement 3, where v_newstype is a variable, if the value of v_newstype is equal to 1, statement 1 is constructed, and if the value of v_newstype is equal to "social news", statement 3 is constructed. But unfortunately, if we ignore the check for v_newstype, statement 2 or statement 4 may also be constructed by this method, for example, the value of v_newstype is "1". Drop table news "or" Social News "; drop table news--, if our carelessness is taken advantage of by others, it will cause us huge losses. SQL injection attacks take advantage of our negligence, so the root of SQL injection attacks comes from improper coding of developers and is not directly related to the platform, development tools, system architecture and so on you use.

At this point, the study on "what is the nature of SQL injection attacks" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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