How to check what user php is running as?

Question

<?php echo exec('whoami'); ?>

If available you can probe the current user account with posix_geteuid and then get the user name with posix_getpwuid.

$username = posix_getpwuid(posix_geteuid())['name'];

If you are running in safe mode however (which is often the case when exec is disabled), then it's unlikely that your PHP process is running under anything but the default www-data or apache account.

Kind of backward way, but without exec/system:

file_put_contents("testFile", "test");
$user = fileowner("testFile");
unlink("testFile");

If you create a file, the owner will be the PHP user.

This could also likely be run with any of the temporary file functions such as tempnam(), which creates a random file in the temporary directory and returns the name of that file. If there are issues due to something like the permissions, open_basedir or safe mode that prevent writing a file, typically, the temp directory will still be allowed.

More details would be useful, but assuming it's a linux system, and assuming php is running under apache, it will run as what ever user apache runs as.

An easy way to check ( again, assuming some unix like environment ) is to create a php file with:

<?php
    print shell_exec( 'whoami' );
?>

which will give you the user.

For my AWS instance, I am getting apache as output when I run this script.

You can try using backticks like this:

echo `whoami`;

i would use:

lsof -i
lsof -i | less
lsof -i | grep :http

any of these. You can type em in your ssh command line and you will see what user is listening what service.

you can also go and check this file:

more /etc/apache2/envvars

and look for these lines:

export APACHE_RUN_USER=user-name
export APACHE_RUN_GROUP=group-name

to filter out envvars file data, you can use grep:

 more  /etc/apache2/envvars |grep APACHE_RUN_

exec('whoami') will do this

<?php
echo exec('whoami');
?>