Cisco Secure Firewall detects suspicious traffic that exhibits scanning-like behavior that originates from a seldom used printer on the network. Which type of Nmap scan is possibly being detected?

If Cisco Secure Firewall detects suspicious traffic exhibiting scanning-like behavior originating from a seldom-used printer on the network, it is possible that a “TCP Idle” scan, also known as an “Idle scan,” is being detected.

The TCP Idle scan is a type of Nmap scan that can be used to stealthily map out a network without revealing the scanner’s IP address. This scan technique involves using a “zombie” host (in this case, the seldom-used printer) to send the scan packets. By manipulating the IP ID sequence numbers of the “zombie” host, the scanner can indirectly scan a target without exposing its own IP address. This type of scan is particularly stealthy and can be difficult to trace back to the actual attacker.

The other scan types mentioned have different characteristics:

• TCP Connect: This is a basic form of scanning that establishes a full TCP connection with the target. It’s not stealthy and can be easily detected.
• TCP SYN Stealth: This scan sends TCP SYN packets to initiate a connection but doesn’t complete the handshake. It’s more stealthy than a TCP Connect scan but still can be traced back to the scanner.
• UDP: This scan targets UDP ports and is used to identify open UDP services on a host. It’s not specifically known for being stealthy in the way an Idle scan is.