Thinfinity VirtualUI before 3.0 allows a malicious actor to enumerate users registered in the OS (Windows) through the /changePassword URI. By accessing the vector, an attacker can determine if a username exists thanks to the message returned; it can be presented in different languages according to the configuration of VirtualUI. Common users are administrator, admin, guest and krgtbt.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-44554
• cybelesoft/virtualui#1