During a penetration testing engagement, you are reviewing server log files and observe a high number of login attempts from foreign IP addresses, frequent access requests for unusual files, and command history that includes reconnaissance tools not used by any team member. These observations are critical to communicate because they could suggest what?
The intrusion detection system is functioning with high accuracy.
The system may have been previously compromised.
The system's firewall is automatically blocking potential threats effectively.
Team members are likely conducting stress tests on the server.
Routine maintenance is being performed by the IT department.
A scheduled backup of server files is in progress.