PRTG Network Monitor before 18.2.40.1683 allows remote unauthenticated attackers to create users with read-write privileges (including administrator). A remote unauthenticated user can craft an HTTP request and override attributes of the 'include' directive in /public/login.htm and perform a Local File Inclusion attack, by including /api/addusers and executing it. By providing the 'id' and 'users' parameters, an unauthenticated attacker can create a user with read-write privileges (including administrator).
PRTG Network Monitor before 18.2.40.1683 allows an authenticated user with a read-only account to create another user with a read-write account (including administrator) via an HTTP request because /api/addusers doesn't check, or doesn't properly check, user rights.
PRTG Network Monitor before 18.3.44.2054 allows a remote authenticated attacker (with read-write privileges) to execute arbitrary code and OS commands with system privileges. When creating an HTTP Advanced Sensor, the user's input in the POST parameter 'proxyport_' is mishandled. The attacker can craft an HTTP request and override the 'writeresult' command-line parameter for HttpAdvancedSensor.exe to store arbitrary data in an arbitrary place on the file system. For example, the attacker can create an executable file in the \Custom Sensors\EXE directory and execute it by creating EXE/Script Sensor.
An issue was discovered in PRTG Network Monitor before 18.2.39. An attacker who has access to the PRTG System Administrator web console with administrative privileges can exploit an OS command injection vulnerability (both on the server and on devices) by sending malformed parameters in sensor or notification management scenarios.
PRTG Network Monitor 17.3.33.2830 allows remote authenticated administrators to execute arbitrary code by uploading a .exe file and then proceeding in spite of the error message.
PRTG Network Monitor version 17.3.33.2830 is vulnerable to stored Cross-Site Scripting on all group names created, related to incorrect error handling for an HTML encoded script.