BullWall Server Intrusion Protection has a noticeable delay before the MFA check when connecting via RDP. A remote authenticated attacker with administrative privileges can potentially bypass detection during this window. Versions 4.6.0.0, 4.6.0.6, 4.6.0.7, and 4.6.1.4 were confirmed to be affected; other versions before and after may also be affected.
The product checks the state of a resource before using that resource, but the resource’s state can change between the check and the use in a way that invalidates the results of the check.