CVE-2020-28405 is a high-severity improper authorization vulnerability identified in Star Practice Management Web version 2019.2.0.6. This vulnerability allows an unauthorized attacker to escalate privileges within the application by changing the privileges of any user account. Specifically, the attacker can grant themselves administrative rights or remove all existing administrative accounts, effectively taking full control over the application. The vulnerability arises due to insufficient access control checks on privilege modification functions, enabling an attacker with low privileges to perform unauthorized privilege changes without requiring user interaction. The CVSS 3.1 base score of 8.8 reflects the critical impact on confidentiality, integrity, and availability, with network attack vector and low attack complexity. Exploitation does not require user interaction but does require some level of privileges (PR:L), indicating that the attacker must have at least limited access to the application, such as a standard user account. There are no known public exploits in the wild, and no patches or vendor information is provided, which may complicate mitigation efforts. The vulnerability affects a specific version of Star Practice Management Web, a software likely used in healthcare or medical practice management environments.

For European organizations, particularly those in the healthcare sector using Star Practice Management Web 2019.2.0.6, this vulnerability poses a significant risk. Unauthorized privilege escalation can lead to full administrative control, allowing attackers to manipulate sensitive patient data, disrupt healthcare operations, or remove legitimate administrative users to maintain persistence. This can result in severe confidentiality breaches of personal health information (PHI), violating GDPR regulations and leading to substantial legal and financial penalties. Additionally, integrity and availability of critical healthcare management systems could be compromised, potentially impacting patient care and operational continuity. The ability to remove all administrative accounts could lock out legitimate administrators, complicating incident response and recovery efforts. Given the critical nature of healthcare data and the regulatory environment in Europe, exploitation of this vulnerability could have far-reaching consequences for affected organizations.

1. Immediate mitigation should include restricting access to the Star Practice Management Web application to trusted users only, ideally through network segmentation and strict access controls. 2. Implement multi-factor authentication (MFA) for all user accounts to reduce the risk of unauthorized access. 3. Conduct a thorough audit of user privileges and remove or limit unnecessary user accounts, especially those with elevated privileges. 4. Monitor application logs for unusual privilege modification activities or administrative account removals. 5. If possible, upgrade or patch the application to a version where this vulnerability is fixed; if no patch is available, consider applying compensating controls such as web application firewalls (WAF) with rules to detect and block unauthorized privilege changes. 6. Educate administrators and users about the risks and signs of privilege escalation attacks. 7. Establish an incident response plan specifically addressing potential exploitation of this vulnerability, including backup and recovery procedures to restore administrative access if locked out.