PHP session changes if variable changes

Question

I have encountered a weird situation:

First I assign variable to a session then I change it. Then the session changes when I change the variable, even when I didn't re-assign the value to the session :

the example (session1.php)

session_start();
$var_test = "first session value";
$_SESSION['var_test'] = $var_test;
echo "$_SESSION['var_test'];

// this will show "first session value"

the second php file (session2.php)

session_start();
$var_test = "second session value !!!";
echo $_SESSION['var_test'];

// this shows "second session value !!!";

In session1.php it shows "first session value" which is perfectly good, but in the second php file (session2.php) it shows "second session value".

Even though I didn't assign $_SESSION['var_test'] = $var_test, how come does it change automatically?

Is that a bug or is it just how it works?

And what happens if you don't change the variable? Just curious. — Shomz
– Shomz, Commented Oct 1, 2014 at 12:59

Philip G · Accepted Answer · 2014-10-01 13:04:41Z

1

This could probably be caused by register_globals=on in php ini. (If you are using an old php version)

try this in your .htaccess file (located in document root):

php_flag register_globals off.

(Our if you have access: change it in php.ini);

register_globals is a security threat for a bad written php application.

answered Oct 1, 2014 at 13:04

Philip G

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5 Comments

user3637384 Over a year ago

I think you are right, my register_globals is currently set as "ON" and I'm using php 5.2.6

user3637384 Over a year ago

Im bit scared if I change it to "OFF" it might crush my entire site as I dont know how will it affect all my pages ... :(

Philip G Over a year ago

You should realy consider to turn it off! But when you do: test your applications since there could be some side effects for your curent scripts if they are poorly written.

Philip G Over a year ago

You could always turn it back on!

Philip G Over a year ago

Glad I could be of help!

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