CVE-2021-45891: 
Homebrew vulnerability analysis and mitigation

An issue was discovered in Softwarebuero Zauner ARC 4.2.0.4 that allows attackers to escalate privileges within the application, since all permission checks are done client-side, not server-side. The vulnerability was discovered in October 2021 and publicly disclosed on April 1, 2022 (SySS Advisory).

The vulnerability is classified as a Client-Side Enforcement of Server-Side Security (CWE-602) issue with a high risk level. The application performs all security checks locally on the client side, including password validation. All communication to the database backend is performed using the same technical account. This implementation allows attackers to bypass security controls by either attaching a debugger to the process or creating patches that manipulate the behavior of security functions (SySS Advisory). The vulnerability has been assigned a CVSS v3.1 base score of 8.8 HIGH (Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) (NVD).

The vulnerability allows attackers to gain administrative privileges over the application. An attacker can bypass authentication mechanisms, privilege level checks, and take direct control over database queries. This could lead to unauthorized access to sensitive data and system functions (SySS Advisory).

The manufacturer has confirmed that this vulnerability will not be fixed in ZA|ARC. Users are advised to upgrade to zaarc.next when it becomes available (SySS Advisory).