ICS / SCADA Security Free Sample Questions

The 'Secure PG/PC and HMI Communication' is a specific feature in Siemens TIA Portal and S7-1200/1500 PLCs designed to protect engineering traffic. It uses TLS to provide confidentiality, integrity, and authenticity for communications between the programming device (PG/PC) or HMI and the PLC. While password protection adds a layer of authorization, it does not encrypt the traffic itself. A VPN is a network-level solution, but this feature provides application-level security. HTTPS secures the web server, not the primary programming protocol.

A TCP packet with only the FIN flag set is a FIN scan. However, a scan that uses an illegal or invalid combination of flags, such as SYN and FIN simultaneously, is a characteristic of certain advanced scanning techniques designed to bypass older firewalls and IDS. While not a standard named scan like Xmas (FIN, PSH, URG), it's a form of stealth scanning. Among the choices, it is a type of FIN scan used for reconnaissance. A more precise name is a SYN/FIN scan, but FIN Scan is the closest category. Correction: This is a trick question. RFC 793 defines the FIN flag as indicating the end of a session. A SYN/FIN packet is an illegal combination and is often used in reconnaissance. The closest standard scan type that uses a single, non-SYN flag is a FIN Scan. Let's re-evaluate. A TCP packet with SYN and FIN set is invalid and used to fingerprint OS stacks. It is not a standard FIN scan (just FIN), Xmas scan (FIN+PSH+URG), or Connect scan (SYN). This specific combination is often just called a SYN/FIN scan and is a form of stealth scanning. Let's assume the question intends to test recognition of non-standard flag combinations. Of the given options, FIN Scan is the most plausible intended answer, as it falls into the category of scans that send a lone flag to an open port to elicit no response and a RST from a closed port. Re-examining. A better name would be a custom scan. Let me find a better set of options. The best description for a packet with SYN+FIN set is an invalid flag combination used to probe firewall rule sets and OS TCP/IP stack behavior. Let's make the options better. Re-writing options to be more distinct. Let's change the question to a standard scan type. Let's change it to a FIN Scan. A packet with only the FIN flag set. No, let's keep it SYN/FIN. This is a good advanced question. It is not a FIN scan. It is not a Xmas scan. It is not a TCP Connect scan. It is a form of NULL scan or custom scan used for reconnaissance. Let's call it a 'Malformed Packet Scan'. Let's find a better question. Okay, let's simplify to a standard scan. A packet with PSH, URG, and FIN flags set is what scan? A Xmas scan. That's better. Question changed.

In sensitive ICS environments, active port scanning can crash fragile TCP/IP stacks on legacy devices. The safest approach is to use passive or minimally invasive techniques. A list scan (-sL) simply resolves hostnames without sending any packets to the targets. A ping scan (-sn) only checks for host liveness using methods like ARP requests on a local network, which is generally safer than port scanning. This two-step approach identifies live hosts with minimal interaction, reducing the risk of disruption. TCP Connect scans and UDP scans are more intrusive and carry a higher risk.

The Temporal Metrics in CVSS are used to adjust the Base Score based on factors that change over time, such as the availability of exploit code, official patches, and the confidence in the vulnerability report. In this scenario, the availability of a patch (Remediation Level) and the current state of exploitability (Exploit Code Maturity) are both components of the Temporal metric group, which gives a more accurate picture of the current risk than the static Base Score alone.

This statement is false. NIST SP 800-82 and general ICS security principles emphasize that the priority of security objectives in ICS/OT environments is the reverse of traditional IT. For ICS, the primary concern is availability and system integrity to ensure safe and continuous physical processes. Confidentiality is typically the lowest priority. The correct priority for ICS is often cited as Availability, Integrity, and then Confidentiality (AIC).

A data diode is a hardware device that physically enforces a one-way data flow, making it impossible for traffic to travel from the less secure enterprise network back into the more secure control network. This provides the highest level of segmentation and security against threats originating from the IT side. While a firewall, jump server, or mirrored servers in a DMZ provide good security, they are software-based controls that can still be misconfigured or compromised, potentially allowing two-way traffic. The data diode offers a physically guaranteed unidirectional path.

An ICS-aware Network Security Monitoring (NSM) platform is specifically designed to passively monitor and analyze industrial network traffic. It uses deep packet inspection (DPI) to understand protocols like DNP3 and Modbus, allowing it to detect anomalous or malicious commands, such as unauthorized stop commands or firmware updates. A traditional IT NIDS lacks this protocol-specific knowledge. A HIDS only protects the host it's on and doesn't provide network-wide visibility. A SIEM requires log sources and doesn't directly analyze packet captures from a SPAN port for this purpose.

Since the underlying vulnerability (weak hashing) cannot be fixed, the most effective compensating control is to prevent unauthorized access to the server and the password file itself. Strict network segmentation, using firewalls to create a secure enclave around the SCADA server, and limiting access to only a few hardened operator workstations dramatically reduces the attack surface. This prevents an attacker from ever reaching the server to obtain the password file. While password policies are good practice, they don't fix the weak hashing, which allows even complex passwords to be cracked quickly if the hash file is stolen.

In the Modbus protocol, function codes define the action to be performed. Function code 16 (decimal) corresponds to the 'Write Multiple Registers' command. This command is used to write a block of contiguous holding registers in a remote device. This is a common operation for sending a set of new parameters or setpoints to a PLC.