<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Introduction</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="security.html">Security</a></div> <div class="next" style="text-align: right; float: right;"><a href="security.general.html">General considerations</a></div> <div class="up"><a href="security.html">Security</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="security.intro" class="chapter"> <h1>Introduction</h1> <p class="simpara"> PHP is a powerful language and the interpreter, whether included in a web server as a module or executed as a separate <acronym title="Common Gateway Interface">CGI</acronym> binary, is able to access files, execute commands and open network connections on the server. These properties make anything run on a web server insecure by default. PHP is designed specifically to be a more secure language for writing <acronym title="Common Gateway Interface">CGI</acronym> programs than Perl or C, and with correct selection of compile-time and runtime configuration options, and proper coding practices, it can give you exactly the combination of freedom and security you need. </p> <p class="simpara"> As there are many different ways of utilizing PHP, there are many configuration options controlling its behaviour. A large selection of options guarantees you can use PHP for a lot of purposes, but it also means there are combinations of these options and server configurations that result in an insecure setup. </p> <p class="simpara"> The configuration flexibility of PHP is equally rivalled by the code flexibility. PHP can be used to build complete server applications, with all the power of a shell user, or it can be used for simple server-side includes with little risk in a tightly controlled environment. How you build that environment, and how secure it is, is largely up to the PHP developer. </p> <p class="simpara"> This chapter starts with some general security advice, explains the different configuration option combinations and the situations they can be safely used, and describes different considerations in coding for different levels of security. </p> </div> <hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="security.html">Security</a></div> <div class="next" style="text-align: right; float: right;"><a href="security.general.html">General considerations</a></div> <div class="up"><a href="security.html">Security</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div></body></html>
