Editing Code injection (section)

===Dynamic evaluation vulnerabilities===
An <syntaxhighlight lang="php" inline>eval()</syntaxhighlight> injection vulnerability occurs when an attacker can control all or part of an input string that is fed into an <syntaxhighlight lang="php" inline>eval()</syntaxhighlight> [[function call]].<ref>{{cite mailing list |author=Christey |first=Steven M. |title=Dynamic Evaluation Vulnerabilities in PHP applications |mailing-list=Full Disclosure |date=3 May 2006 |url=https://seclists.org/fulldisclosure/2006/May/35 |access-date=2018-10-21 |archive-url=https://web.archive.org/web/20091113113128/https://seclists.org/fulldisclosure/2006/May/35 |archive-date=13 November 2009 |url-status=live}}</ref>
<syntaxhighlight lang="php">
$myvar = 'somevalue';
$x = $_GET['arg'];
eval('$myvar = ' . $x . ';');
</syntaxhighlight>
The argument of "<code>[[eval]]</code>" will be processed as [[PHP]], so additional commands can be appended. For example, if "arg" is set to "<syntaxhighlight lang="php" inline>10; system('/bin/echo uh-oh')</syntaxhighlight>", additional code is run which executes a program on the server, in this case "<code>/bin/echo</code>".