How to avoid file paths exposing security issues in PHP language development?

With the continuous development of Internet technology, website security issues have become increasingly prominent, among which file path exposure security issues are a common one. File path exposure means that the attacker can learn the directory information of the website program through some means, thereby further obtaining the website's sensitive information and attacking the website. This article will introduce the security issues of file path exposure in PHP language development and their solutions.

1. The principle of file path exposure

In PHP program development, we usually use relative paths or absolute paths to access files, as shown below:

Relative paths: include ("header.php");

Absolute path: include("d:/wwwroot/header.php");

In the above code, if the attacker obtains If you know the true path of the file, you can obtain the sensitive information of the website by accessing the file under the path.

2. Hazards of file path exposure

If an attacker obtains sensitive information of the website through file path exposure, the following harm may occur:

1. The site is compromised Hacked, data has been tampered with, or even hacked;
2. Personal information leaked, including user privacy information, operating habits, etc.;
3. Database utilization, modification and deletion of data, and acquisition of relevant sensitive information;
4. The server was attacked, including DDOS, SQL injection, etc.

3. Methods to avoid file path exposure

1. Disable error message

PHP’s error message is very detailed. If it is displayed , may contain sensitive file path information. Therefore, in order to avoid the exposure of file path information, we can disable the error message or output it to a log file instead of directly outputting it to the front-end interface, as shown below:

error_reporting(0);

2. Define constants

In the program, we can use constants to replace the absolute path, so that even if the attacker obtains the directory information where the program is running through some means, he cannot pass the The information obtains the real path of the file, as follows:

define('APPPath',dirname(__FILE__));

3. Check the file path

Use functions such as is_file() in the code to check the legality of the file path. If an attacker attacks by changing the parameters in the URL, if the file name does not exist, an error will be returned immediately without any response. If it exists, the execution of the operation can be generalized, and the attacker will have an interface to perform the operation, which is undesirable by the developer because it would be extremely dangerous. Therefore we need to check the validity of the file path as follows:

if(is_file($fileName)){

//执行操作

}else{

//返回404页面

}

4. Turn off the Apache directory browsing function

When the file path is exposed, an attacker may use the Apache directory browsing function to view the directory structure of the website and obtain sensitive information of the website. Therefore, we need to turn off the directory browsing function in the Apache configuration file:

Options -Indexes

5. Use URL rewriting

In order to avoid the disclosure of the URL , one way is to rewrite the URL. URL rewriting refers to modifying the format of the URL to make the URL more friendly and beautiful, and to hide the true path of the website. URL rewriting needs to be configured on the server. For specific methods, please refer to the relevant documentation of the server.

4. Conclusion

File path exposure is a very easy security issue and should be taken seriously in PHP program development. In order to avoid file path exposure, we can take various methods, such as disabling error prompts, defining constants, checking file paths, turning off Apache directory browsing functions, and using URL rewriting. By using these measures appropriately, we can better protect the security of PHP programs.

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