PHP Safe Mode safe_mode Configuration tutorial and detailed

Source: Internet
Author: User
Tags file handling phpinfo apache log

(1) Open PHP Safe mode
PHP's security model is a very important embedded security mechanism to control some functions in PHP, such as System (),
At the same time, a lot of file operation functions have permission control, also does not allow the files for some key files, such as/etc/passwd,
But the default php.ini is not open in Safe mode, we turn it on:


Safe_mode = On


(2) User group security
When Safe_mode is turned on, Safe_mode_gid is turned off, and the PHP script is able to access the file, and the same
Users of the group are also able to access the files.
The recommended setting is:


Safe_mode_gid = Off


If we do not set up, we may not be able to operate the files in our server web directory, for example, we need to
When you are working on a file.


(3) Execute Program home directory in Safe mode
If Safe mode is turned on, but you want to execute some programs, you can specify the home directory where you want to execute the program:


Safe_mode_exec_dir = D:/usr/bin


In general, do not need to execute what program, so it is recommended not to execute the System program directory, can point to a directory,
Then copy the program that needs to be executed, such as:


Safe_mode_exec_dir = D:/tool/exe


However, I recommend that you do not execute any programs, then you can point to our web directory:


Safe_mode_exec_dir = d:/usr/www


(4) Include files in Safe mode
If you want to include some common files in Safe mode, then modify the options:


Safe_mode_include_dir = d:/usr/www/include/


In fact, the general PHP script contains files are in the program itself has been written, this can be set according to the specific needs.


(5) control the directory that PHP scripts can access
Use the OPEN_BASEDIR option to control the PHP script to access only the specified directory, which avoids the PHP script access
The files that should not be accessed to some extent limit the harm of phpshell, we can generally be set to only access the site directory:


Open_basedir = d:/usr/www


(6) Close danger function
If Safe mode is turned on, then the function prohibition is not necessary, but we consider it to be safe. Like what
We don't want to execute PHP functions that include the system (), or the ability to execute commands, or the ability to view PHP information
Phpinfo () and so on, then we can disable them:


Disable_functions = System,passthru,exec,shell_exec,popen,phpinfo


If you want to disable the operation of any files and directories, you can close many file operations


Disable_functions=chdir,chroot,dir,getcwd,opendir,readdir,scandir,fopen,unlink,delete,
Copy,mkdir,rmdir,rename,file,file_get_contents,fputs,fwrite,chgrp,chmod,chown


These are just a few of the most commonly used file handling functions, and you can also combine the above command functions with this function,
will be able to resist most of the Phpshell.


(7) Close the PHP version information in the HTTP header leak
In order to prevent hackers from getting the PHP version of the server information, you can close the information ramp in the HTTP header:


expose_php = Off


For example, when the hacker in Telnet www.target.com 80, then will not see the PHP information.


(8) Close registered global variables
Variables submitted in PHP, including those that use post or get commits, are automatically registered as global variables and can be accessed directly,
This is very insecure for the server, so we can't register it as a global variable, and turn off the Register global variables option:


Register_globals = Off


Of course, if this is set, then the corresponding variable should be taken in a reasonable way, such as get the variable var of get commit,
Then you need to use $_get[' var ' to get it, this PHP programmer should pay attention to.


(9) Open MAGIC_QUOTES_GPC to prevent SQL injection


SQL injection is a very dangerous problem, small site background was invaded, heavy the entire server fell,


So be sure to be careful. There is a setting in php.ini:


MAGIC_QUOTES_GPC = Off


This is off by default, and if it is turned on, it will automatically convert the query that the user commits to SQL.
It's important to prevent SQL injections, for example, by turning ' switch '. So we recommend setting it to:


MAGIC_QUOTES_GPC = On


(10) Error Message control


In general, PHP is not connected to the database or in other cases there will be a prompt error, the general error message will contain PHP script when
Before the path information or query SQL statements and other information, such information provided to the hacker is not secure, so the general server recommended to suppress the error prompt

Display_errors = Off


If you are trying to display an error message, be sure to set the level of display errors, such as displaying only the information above the warning:


error_reporting = e_warning & E_error


Of course, I recommend turning off the error prompt.


(11) Error log
It is recommended to log the error message after closing the display_errors to find out why the server is running:


Log_errors = On


Also set the directory where the error log is stored, suggesting that the root Apache log exists together:


Error_log = D:/usr/local/apache2/logs/php_error.log


Note: The to file must allow Apache users and groups to have write permissions.


MySQL's Down right run
Create a new user like MySQL


NET user MySQL Mysql/add
net localgroup users Mysql/del


Does not belong to any group


If MySQL is installed in d:mysql, then give MySQL Full control of the permissions, then set in system services, MySQL service properties, in the login properties, select this user MySQL and then enter


Password, OK. Restart the MySQL service, and then MySQL runs under low authority.
Apache's Down right run


The Apache default operation under the Windows platform is the system privilege, which gives Apache permission to drop down.


NET user Apache Apche/add
net localgroup users Apache/del


We have created a user apche that does not belong to any group.
We open the Computer Manager, select the service, point to the properties of the Apache service, we choose Log on, select the This account, we fill in the accounts and passwords established above, restart the Apache service, OK


, Apache runs under low authority.
In fact, we can also set individual folder permissions, so that Apache users can only do what we want it to do, to each directory to create a separate read and write users.

PHP Safe Mode safe_mode Configuration tutorial and detailed

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