Summary of some safe hidden codes in php_PHP tutorial

The security of program code is a reflection of a programmer’s multi-faceted qualities in developing applications. Let me summarize my experience below. Friends who need to know more can refer to it.

Baidu. After setting open_basedir, only php scripts in the specified directory and subdirectory will be executed.
Using php to read directories or files other than open_basedir will report an error
Insufficient permissions
Generally, virtual host providers are set to /tmp and /home

This is what users are used to. We need to find ways to solve these problems. Here is a summary of some PHP security issues.

1. Be careful when including. Check whether you have this file locally to avoid security vulnerabilities.
For example:

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include $module.'.php'; ?>

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Include $module.'.php';
?>

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if(file_exists($module.'.php')){         include $module.'.php';     } ?>

It is assumed here that $module is function/42833.htm target=_blank>global variable.
This script gives the attacker the opportunity to execute any PHP code on your server. For example, he can just add ?module=http://example.com/my after the browser URL. When PHP receives this URL, the value of the "$module" variable in the script will be set to http://example.com/my. Therefore, it is very dangerous when php executes include...
Solution: Check when closing register_globals or include in php.ini.

2. Run scripts across sites. Simply put, an attacker can execute some client-side scripts, such as js, on the user's browser, and then steal the user's cookies or other important data.

The code is as follows

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$query "select login_id from users where user='$user' and pwd='$pw'";     mysql_query($query); ?>

If(file_exists($module.'.php')){
include $module.'.php';
} ?>

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$query = "select login_id from user where user='admin' or (user = '' and pwd='') or user=''";     mysql_query($query); ?>

For example If you click the button, your local cookie information will be sent to someone's email address (this shows how easy it is to create a website that steals user information). 3.SQL injection Personally, I feel that the flexibility and ease of use of SQL itself have a negative impact on me.

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$query "select login_id from users where user='$user' and pwd='$pw'"; Mysql_query($query); ?> For example, if someone writes it http://example.com/login.php?user=admin'%20OR%20(user='&pwd=')%20R%20user=' Your php code may become.

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$query = "select login_id from user where user='admin' or (user = '' and pwd='') or user=''"; Mysql_query($query); ?> You can use functions to filter out (') ("), (), etc. http://www.bkjia.com/PHPjc/629659.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/629659.htmlTechArticleThe security of program code is a programmer’s multi-faceted quality in developing applications. Let me summarize it below Let’s talk about my own experience, and friends who need to know more can refer to it. Baidu one...