Description

Cross-Site Scripting (XSS) attacks are a type of injection, in which malicious scripts are injected into otherwise benign and trusted websites. XSS attacks occur when an attacker uses a web application to send malicious code, generally in the form of a browser side script, to a different end user. Flaws that allow these attacks to succeed are quite widespread and occur anywhere a web application uses input from a user within the output it generates without validating or encoding it.

Proof of Concept

1. Go to Virtual desk > Calendar

2. Add a Meeting/Call/To Do, put a XSS payload into Meeting URL field. E.g: https://www.google.com/#"><img/src/onerror=alert('xss')>

3. Save then back to Calendar, click on the event just add above, click to the Meeting URL and XSS script will executed

Impact

XSS can have huge implications for a web application and its users. User accounts can be hijacked, change the html screen and insult the organization. Credentials could be stolen, sensitive data could be exfiltrated, and lastly, access to your client computers can be obtained.