I could not find the reason why my request fail for the following
My php code is:
if (isset($_COOKIE["user"])) {
echo '<p><h3><strong>Welcome '.$_COOKIE["param"].'</strong></h3></p>'; .....
When i request exec('ls -al') as param , the php code did not run the command.
On the response of the request it was like parameterized:
Welcome exec('ls -al')
What may the reason that failed this execution?
$_COOKIE["param"] is a string. You are echoing it. It is not supposed to run anything.
If you wanted to run a command in your PHP, you would have to use eval(). But as for running a command from a cookie value:
DON'T DO IT!
echo '<p><h3><strong>Welcome '."exec('ls -al)".'</strong></h3></p>';, notice the ". This WILL echo exec('ls -al)So you're saying that the value of $_COOKIE['param'] is exec('ls -al'), and you're expecting that to run when you echo it out?
That's not how it works. The value of that cookie will be the string value "exec('ls -al')", not the result of the executed code. If you think about it for a second, you'll understand why it would be a bad idea for a cookie to be able to auto-execute code.
It's not really a great idea to be running random commands through exec() anyway, especially if that input came from a user (which cookies do - the user can and will change them to try to attack you).
Instead, you should be using other input that your code can interpret as a signal to run certain code. For example, you could have the param value hold the string list files, and your code would see that value and run exec('ls -al') for you.
You still shouldn't be execing code to do this though, since it's very easy to accidentally run dangerous commands that way. Instead, you should use PHP's built-in functions as much as possible, and only after sanitizing your inputs and only running known values.
For your case, PHP has a bunch of functions that let you interact with the filesystem of your server. Use those to get a list of files on the system instead.