# SEAS-8414 Phase 6 Homework
## Blackboard Multiple-Choice Assessment: Digital Twin and Remediation Simulation

**Due:** Before Class 7, 9:00 AM ET
**Total Points:** 100
**Format:** 50 single-correct-answer multiple choice questions, 2 points each
**Audience:** Doctoral students and senior cybersecurity practitioners

This assessment is designed for Blackboard delivery. Every item is multiple choice
with exactly one correct answer. The assessment is closed book: do not use the
textbook, notes, internet search, lab files, scanners, AI tools, or outside
incident writeups while answering.

Each question includes a scenario-provenance label. That label is a citation
trail for instructors and is never required to choose the answer. Every formula,
threshold, rule, or evidence contract required to answer appears inside the stem.

Chapter boundary: answer only within simulation cyber analytics for IoT/OT remediation. Do not import later
chapter capabilities unless the stem explicitly defines them.

---

### Question 1

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility computes Chapter 6 per-device remediation risk. Port weights are Telnet
23=15, Modbus 502=12, RTSP 554=10, MQTT 1883=8, HTTP 80=5, HTTPS 443=3. Each any-source
allow rule adds 2.0. Default credential risk is Telnet=20, RTSP=12, HTTP=8, MQTT=7. Each
unpatched CVE adds 3.0. The device has ports [23, 502, 80], 2 any-source allow rules,
default credentials on Telnet, and 3 CVEs. Which risk score is correct?

(a) 41.0
(b) 56.0
(c) 13.0
(d) 65.0

### Question 2

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

A power cooperative computes Chapter 6 per-device remediation risk. Port weights are
Telnet 23=15, Modbus 502=12, RTSP 554=10, MQTT 1883=8, HTTP 80=5, HTTPS 443=3. Each
any-source allow rule adds 2.0. Default credential risk is Telnet=20, RTSP=12, HTTP=8,
MQTT=7. Each unpatched CVE adds 3.0. The device has ports [502, 80], 1 any-source allow
rules, default credentials on no protocol, and 2 CVEs. Which risk score is correct?

(a) 19.0
(b) 8.0
(c) 25.0
(d) 23.0

### Question 3

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A pipeline operator computes Chapter 6 per-device remediation risk. Port weights are
Telnet 23=15, Modbus 502=12, RTSP 554=10, MQTT 1883=8, HTTP 80=5, HTTPS 443=3. Each
any-source allow rule adds 2.0. Default credential risk is Telnet=20, RTSP=12, HTTP=8,
MQTT=7. Each unpatched CVE adds 3.0. The device has ports [554, 80, 443], 3 any-source
allow rules, default credentials on RTSP, and 4 CVEs. Which risk score is correct?

(a) 18.0
(b) 48.0
(c) 30.0
(d) 36.0

### Question 4

**Scenario provenance only (not needed to answer):** OASIS STIX 2.1 standard.

A maritime port authority computes Chapter 6 per-device remediation risk. Port weights
are Telnet 23=15, Modbus 502=12, RTSP 554=10, MQTT 1883=8, HTTP 80=5, HTTPS 443=3. Each
any-source allow rule adds 2.0. Default credential risk is Telnet=20, RTSP=12, HTTP=8,
MQTT=7. Each unpatched CVE adds 3.0. The device has ports [1883, 443], 2 any-source
allow rules, default credentials on MQTT, and 1 CVEs. Which risk score is correct?

(a) 25.0
(b) 14.0
(c) 22.0
(d) 7.0

### Question 5

**Scenario provenance only (not needed to answer):** FIRST CVSS v3.1 specification.

A hospital medical-device program computes Chapter 6 per-device remediation risk. Port
weights are Telnet 23=15, Modbus 502=12, RTSP 554=10, MQTT 1883=8, HTTP 80=5, HTTPS
443=3. Each any-source allow rule adds 2.0. Default credential risk is Telnet=20,
RTSP=12, HTTP=8, MQTT=7. Each unpatched CVE adds 3.0. The device has ports [23, 443], 1
any-source allow rules, default credentials on Telnet, and 1 CVEs. Which risk score is
correct?

(a) 21.0
(b) 40.0
(c) 5.0
(d) 43.0

### Question 6

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

A power cooperative remediation preview compares a checkpointed pre-remediation topology
against the post-remediation topology. The pre-remediation risk is 65.0; the
post-remediation risk is 17.0. Chapter 6 defines delta as post minus pre, so negative
means risk fell. Which delta statement is correct?

(a) Delta -48.0; risk reduction 26.2%.
(b) No delta can be computed after remediation because the checkpoint is mutated.
(c) Delta -48.0; risk reduction 73.8%.
(d) Delta 48.0; risk increased by 73.8%.

### Question 7

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A pipeline operator remediation preview compares a checkpointed pre-remediation topology
against the post-remediation topology. The pre-remediation risk is 54.0; the
post-remediation risk is 21.0. Chapter 6 defines delta as post minus pre, so negative
means risk fell. Which delta statement is correct?

(a) No delta can be computed after remediation because the checkpoint is mutated.
(b) Delta -33.0; risk reduction 61.1%.
(c) Delta 33.0; risk increased by 61.1%.
(d) Delta -33.0; risk reduction 38.9%.

### Question 8

**Scenario provenance only (not needed to answer):** OASIS STIX 2.1 standard.

A maritime port authority remediation preview compares a checkpointed pre-remediation
topology against the post-remediation topology. The pre-remediation risk is 40.0; the
post-remediation risk is 22.0. Chapter 6 defines delta as post minus pre, so negative
means risk fell. Which delta statement is correct?

(a) Delta -18.0; risk reduction 45.0%.
(b) Delta 18.0; risk increased by 45.0%.
(c) Delta -18.0; risk reduction 55.0%.
(d) No delta can be computed after remediation because the checkpoint is mutated.

### Question 9

**Scenario provenance only (not needed to answer):** FIRST CVSS v3.1 specification.

A hospital medical-device program remediation preview compares a checkpointed
pre-remediation topology against the post-remediation topology. The pre-remediation risk
is 88.0; the post-remediation risk is 36.0. Chapter 6 defines delta as post minus pre,
so negative means risk fell. Which delta statement is correct?

(a) Delta 52.0; risk increased by 59.1%.
(b) Delta -52.0; risk reduction 40.9%.
(c) No delta can be computed after remediation because the checkpoint is mutated.
(d) Delta -52.0; risk reduction 59.1%.

### Question 10

**Scenario provenance only (not needed to answer):** Yen 1971 k-shortest loopless paths paper.

A rail signaling operator remediation preview compares a checkpointed pre-remediation
topology against the post-remediation topology. The pre-remediation risk is 72.0; the
post-remediation risk is 30.0. Chapter 6 defines delta as post minus pre, so negative
means risk fell. Which delta statement is correct?

(a) Delta -42.0; risk reduction 41.7%.
(b) No delta can be computed after remediation because the checkpoint is mutated.
(c) Delta -42.0; risk reduction 58.3%.
(d) Delta 42.0; risk increased by 58.3%.

### Question 11

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A pipeline operator runs 10,000 Chapter 6 Monte Carlo trials for a patch plan. The BRS
delta mean is -372, the 95% interval is [-425, -318], and P(max-offline violation)=0.02.
Negative BRS delta means risk decreased. Which interpretation follows?

(a) A negative mean delta means every individual trial reduced risk.
(b) The simulation supports a risk decrease across the 95% interval, and the offline-limit violation probability is 2%.
(c) The plan is guaranteed safe because Monte Carlo uses 10,000 trials.
(d) P(max-offline violation) is the percentage of devices that remain vulnerable.

### Question 12

**Scenario provenance only (not needed to answer):** OASIS STIX 2.1 standard.

A maritime port authority runs 10,000 Chapter 6 Monte Carlo trials for a patch plan. The
BRS delta mean is -210, the 95% interval is [-260, -150], and P(max-offline
violation)=0.08. Negative BRS delta means risk decreased. Which interpretation follows?

(a) The simulation supports a risk decrease across the 95% interval, and the offline-limit violation probability is 8%.
(b) The plan is guaranteed safe because Monte Carlo uses 10,000 trials.
(c) P(max-offline violation) is the percentage of devices that remain vulnerable.
(d) A negative mean delta means every individual trial reduced risk.

### Question 13

**Scenario provenance only (not needed to answer):** FIRST CVSS v3.1 specification.

A hospital medical-device program runs 10,000 Chapter 6 Monte Carlo trials for a patch
plan. The BRS delta mean is -95, the 95% interval is [-130, -60], and P(max-offline
violation)=0.00. Negative BRS delta means risk decreased. Which interpretation follows?

(a) The plan is guaranteed safe because Monte Carlo uses 10,000 trials.
(b) P(max-offline violation) is the percentage of devices that remain vulnerable.
(c) A negative mean delta means every individual trial reduced risk.
(d) The simulation supports a risk decrease across the 95% interval, and the offline-limit violation probability is 0%.

### Question 14

**Scenario provenance only (not needed to answer):** Yen 1971 k-shortest loopless paths paper.

A rail signaling operator runs 10,000 Chapter 6 Monte Carlo trials for a patch plan. The
BRS delta mean is -500, the 95% interval is [-620, -410], and P(max-offline
violation)=0.12. Negative BRS delta means risk decreased. Which interpretation follows?

(a) P(max-offline violation) is the percentage of devices that remain vulnerable.
(b) A negative mean delta means every individual trial reduced risk.
(c) The simulation supports a risk decrease across the 95% interval, and the offline-limit violation probability is 12%.
(d) The plan is guaranteed safe because Monte Carlo uses 10,000 trials.

### Question 15

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A food processing plant runs 10,000 Chapter 6 Monte Carlo trials for a patch plan. The
BRS delta mean is -44, the 95% interval is [-80, -10], and P(max-offline
violation)=0.03. Negative BRS delta means risk decreased. Which interpretation follows?

(a) A negative mean delta means every individual trial reduced risk.
(b) The simulation supports a risk decrease across the 95% interval, and the offline-limit violation probability is 3%.
(c) The plan is guaranteed safe because Monte Carlo uses 10,000 trials.
(d) P(max-offline violation) is the percentage of devices that remain vulnerable.

### Question 16

**Scenario provenance only (not needed to answer):** OASIS STIX 2.1 standard.

A maritime port authority patch scheduler has 40 identical controllers, a
maximum-offline constraint of 3, and a conservative per-group reboot window of 180
seconds. Ignore dependency conflicts for this calculation and fill each group to the
max-offline limit except the final group. Which minimum group count and conservative
total time follow?

(a) 14 groups and 2520 seconds.
(b) 13 groups and 2340 seconds.
(c) 40 groups and 7200 seconds.
(d) 3 groups and 540 seconds.

### Question 17

**Scenario provenance only (not needed to answer):** FIRST CVSS v3.1 specification.

A hospital medical-device program patch scheduler has 24 identical controllers, a
maximum-offline constraint of 4, and a conservative per-group reboot window of 120
seconds. Ignore dependency conflicts for this calculation and fill each group to the
max-offline limit except the final group. Which minimum group count and conservative
total time follow?

(a) 5 groups and 600 seconds.
(b) 24 groups and 2880 seconds.
(c) 4 groups and 480 seconds.
(d) 6 groups and 720 seconds.

### Question 18

**Scenario provenance only (not needed to answer):** Yen 1971 k-shortest loopless paths paper.

A rail signaling operator patch scheduler has 18 identical controllers, a
maximum-offline constraint of 2, and a conservative per-group reboot window of 240
seconds. Ignore dependency conflicts for this calculation and fill each group to the
max-offline limit except the final group. Which minimum group count and conservative
total time follow?

(a) 18 groups and 4320 seconds.
(b) 2 groups and 480 seconds.
(c) 9 groups and 2160 seconds.
(d) 8 groups and 1920 seconds.

### Question 19

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A food processing plant patch scheduler has 35 identical controllers, a maximum-offline
constraint of 5, and a conservative per-group reboot window of 150 seconds. Ignore
dependency conflicts for this calculation and fill each group to the max-offline limit
except the final group. Which minimum group count and conservative total time follow?

(a) 5 groups and 750 seconds.
(b) 7 groups and 1050 seconds.
(c) 6 groups and 900 seconds.
(d) 35 groups and 5250 seconds.

### Question 20

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site patch scheduler has 12 identical controllers, a
maximum-offline constraint of 3, and a conservative per-group reboot window of 300
seconds. Ignore dependency conflicts for this calculation and fill each group to the
max-offline limit except the final group. Which minimum group count and conservative
total time follow?

(a) 4 groups and 1200 seconds.
(b) 3 groups and 900 seconds.
(c) 12 groups and 3600 seconds.
(d) 5 groups and 1500 seconds.

### Question 21

**Scenario provenance only (not needed to answer):** FIRST CVSS v3.1 specification.

A hospital medical-device program builds a Chapter 6 twin. The profile mapper priority
order is: direct device-type lookup first, port-based inference second, and service-name
hinting third. The evidence is device_type='plc' and ports [502,80]. Which mapping tier
should be used first?

(a) port inference first, because ports are always more reliable than device type.
(b) service-name hinting first, because banners contain vendor strings.
(c) random profile assignment, because digital twins cannot map heterogeneous IoT devices.
(d) device-type lookup; telnet-vuln or industrial profile from type evidence.

### Question 22

**Scenario provenance only (not needed to answer):** Yen 1971 k-shortest loopless paths paper.

A rail signaling operator builds a Chapter 6 twin. The profile mapper priority order is:
direct device-type lookup first, port-based inference second, and service-name hinting
third. The evidence is unknown type and ports [554,80]. Which mapping tier should be
used first?

(a) service-name hinting first, because banners contain vendor strings.
(b) random profile assignment, because digital twins cannot map heterogeneous IoT devices.
(c) port inference; RTSP/camera profile from specific port evidence.
(d) port inference first, because ports are always more reliable than device type.

### Question 23

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A food processing plant builds a Chapter 6 twin. The profile mapper priority order is:
direct device-type lookup first, port-based inference second, and service-name hinting
third. The evidence is unknown type, no distinctive ports, service banner contains 'MQTT
broker'. Which mapping tier should be used first?

(a) random profile assignment, because digital twins cannot map heterogeneous IoT devices.
(b) service-name hinting; MQTT profile from service hint.
(c) port inference first, because ports are always more reliable than device type.
(d) service-name hinting first, because banners contain vendor strings.

### Question 24

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site builds a Chapter 6 twin. The profile mapper priority order
is: direct device-type lookup first, port-based inference second, and service-name
hinting third. The evidence is device_type='camera' and ports [80,554]. Which mapping
tier should be used first?

(a) device-type lookup; camera profile from type evidence.
(b) port inference first, because ports are always more reliable than device type.
(c) service-name hinting first, because banners contain vendor strings.
(d) random profile assignment, because digital twins cannot map heterogeneous IoT devices.

### Question 25

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator builds a Chapter 6 twin. The profile mapper priority order is:
direct device-type lookup first, port-based inference second, and service-name hinting
third. The evidence is unknown type and ports [1883,443]. Which mapping tier should be
used first?

(a) port inference first, because ports are always more reliable than device type.
(b) service-name hinting first, because banners contain vendor strings.
(c) random profile assignment, because digital twins cannot map heterogeneous IoT devices.
(d) port inference; MQTT profile from port evidence.

### Question 26

**Scenario provenance only (not needed to answer):** Yen 1971 k-shortest loopless paths paper.

A rail signaling operator replays the same Chapter 6 attack scenario twice against the
same unchanged twin. The scenario engine uses deterministic hashing over target IP,
technique, and step count instead of random number generation. Which result should the
analyst expect?

(a) All attack steps against the same target must either all succeed or all fail.
(b) The scenario cannot be used after remediation because determinism forbids topology changes.
(c) The same compromised hosts and blast radius should repeat; later differences after remediation can be attributed to topology or state changes rather than random noise.
(d) Different hosts should be compromised each run, proving the simulation explores uncertainty.

### Question 27

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A food processing plant replays the same Chapter 6 attack scenario twice against the
same unchanged twin. The scenario engine uses deterministic hashing over target IP,
technique, and step count instead of random number generation. Which result should the
analyst expect?

(a) The scenario cannot be used after remediation because determinism forbids topology changes.
(b) The same compromised hosts and blast radius should repeat; later differences after remediation can be attributed to topology or state changes rather than random noise.
(c) Different hosts should be compromised each run, proving the simulation explores uncertainty.
(d) All attack steps against the same target must either all succeed or all fail.

### Question 28

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site replays the same Chapter 6 attack scenario twice against
the same unchanged twin. The scenario engine uses deterministic hashing over target IP,
technique, and step count instead of random number generation. Which result should the
analyst expect?

(a) The same compromised hosts and blast radius should repeat; later differences after remediation can be attributed to topology or state changes rather than random noise.
(b) Different hosts should be compromised each run, proving the simulation explores uncertainty.
(c) All attack steps against the same target must either all succeed or all fail.
(d) The scenario cannot be used after remediation because determinism forbids topology changes.

### Question 29

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator replays the same Chapter 6 attack scenario twice against the
same unchanged twin. The scenario engine uses deterministic hashing over target IP,
technique, and step count instead of random number generation. Which result should the
analyst expect?

(a) Different hosts should be compromised each run, proving the simulation explores uncertainty.
(b) All attack steps against the same target must either all succeed or all fail.
(c) The scenario cannot be used after remediation because determinism forbids topology changes.
(d) The same compromised hosts and blast radius should repeat; later differences after remediation can be attributed to topology or state changes rather than random noise.

### Question 30

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A baggage-handling operator replays the same Chapter 6 attack scenario twice against the
same unchanged twin. The scenario engine uses deterministic hashing over target IP,
technique, and step count instead of random number generation. Which result should the
analyst expect?

(a) All attack steps against the same target must either all succeed or all fail.
(b) The scenario cannot be used after remediation because determinism forbids topology changes.
(c) The same compromised hosts and blast radius should repeat; later differences after remediation can be attributed to topology or state changes rather than random noise.
(d) Different hosts should be compromised each run, proving the simulation explores uncertainty.

### Question 31

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A food processing plant cascade detector evaluates taking an MQTT broker offline.
Chapter 6 dependency heuristics state that devices exposing port 1883 or 8883 are
brokers, and same-subnet sensors/thermostats are dependents. The topology contains 12
affected same subnet sensors. Which cascade statement follows?

(a) Delete the remediation action because all cascades are proof of compromise.
(b) Report a cascading-failure risk affecting 12 same subnet sensors.
(c) Report no cascade because only the remediated device can be affected.
(d) Report a credential cascade only if CISA KEV also matches.

### Question 32

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site cascade detector evaluates taking an gateway offline.
Chapter 6 dependency heuristics state that router or gateway devices are infrastructure
for same-subnet devices. The topology contains 18 affected same subnet devices. Which
cascade statement follows?

(a) Report a cascading-failure risk affecting 18 same subnet devices.
(b) Report no cascade because only the remediated device can be affected.
(c) Report a credential cascade only if CISA KEV also matches.
(d) Delete the remediation action because all cascades are proof of compromise.

### Question 33

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator cascade detector evaluates taking an historian service
offline. Chapter 6 dependency heuristics state that firewall rules to a service imply
dependency on that destination service. The topology contains 7 affected clients with
firewall rules to that service. Which cascade statement follows?

(a) Report no cascade because only the remediated device can be affected.
(b) Report a credential cascade only if CISA KEV also matches.
(c) Delete the remediation action because all cascades are proof of compromise.
(d) Report a cascading-failure risk affecting 7 clients with firewall rules to that service.

### Question 34

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A baggage-handling operator cascade detector evaluates taking an MQTT broker offline.
Chapter 6 dependency heuristics state that devices exposing port 1883 or 8883 are
brokers, and same-subnet sensors/thermostats are dependents. The topology contains 9
affected same subnet thermostats. Which cascade statement follows?

(a) Report a credential cascade only if CISA KEV also matches.
(b) Delete the remediation action because all cascades are proof of compromise.
(c) Report a cascading-failure risk affecting 9 same subnet thermostats.
(d) Report no cascade because only the remediated device can be affected.

### Question 35

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility cascade detector evaluates taking an router offline. Chapter 6
dependency heuristics state that router or gateway devices are infrastructure for
same-subnet devices. The topology contains 25 affected same subnet devices. Which
cascade statement follows?

(a) Delete the remediation action because all cascades are proof of compromise.
(b) Report a cascading-failure risk affecting 25 same subnet devices.
(c) Report no cascade because only the remediated device can be affected.
(d) Report a credential cascade only if CISA KEV also matches.

### Question 36

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site defines twin fidelity as the average device-profile
confidence. The deployment gate requires fidelity >= 0.70. Four mapped devices have
confidences 0.9, 0.8, 0.7, 0.6. Which gate decision follows?

(a) Fidelity 0.75; pass the gate.
(b) Fidelity 0.90; pass if any device maps well.
(c) Fidelity 0.60; fail if any device is weak.
(d) The gate always passes because simulation results are only advisory.

### Question 37

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator defines twin fidelity as the average device-profile
confidence. The deployment gate requires fidelity >= 0.75. Four mapped devices have
confidences 0.9, 0.9, 0.8, 0.8. Which gate decision follows?

(a) Fidelity 0.90; pass if any device maps well.
(b) Fidelity 0.80; fail if any device is weak.
(c) The gate always passes because simulation results are only advisory.
(d) Fidelity 0.85; pass the gate.

### Question 38

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A baggage-handling operator defines twin fidelity as the average device-profile
confidence. The deployment gate requires fidelity >= 0.70. Four mapped devices have
confidences 0.4, 0.5, 0.6, 0.7. Which gate decision follows?

(a) Fidelity 0.40; fail if any device is weak.
(b) The gate always passes because simulation results are only advisory.
(c) Fidelity 0.55; fail the gate.
(d) Fidelity 0.70; pass if any device maps well.

### Question 39

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility defines twin fidelity as the average device-profile confidence. The
deployment gate requires fidelity >= 0.80. Four mapped devices have confidences 0.95,
0.85, 0.9, 0.8. Which gate decision follows?

(a) The gate always passes because simulation results are only advisory.
(b) Fidelity 0.88; pass the gate.
(c) Fidelity 0.95; pass if any device maps well.
(d) Fidelity 0.80; fail if any device is weak.

### Question 40

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

A power cooperative defines twin fidelity as the average device-profile confidence. The
deployment gate requires fidelity >= 0.60. Four mapped devices have confidences 0.3,
0.4, 0.5, 0.6. Which gate decision follows?

(a) Fidelity 0.45; fail the gate.
(b) Fidelity 0.60; pass if any device maps well.
(c) Fidelity 0.30; fail if any device is weak.
(d) The gate always passes because simulation results are only advisory.

### Question 41

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator runs Chapter 6 zero-disruption validation. The four checks are
port reachability, orphaned firewall rules, bridge integrity, and critical
infrastructure connectivity. The result is: a firewall rule references a device removed
from the topology. Which validation decision follows?

(a) Pass because the BRS delta is negative.
(b) Fail only if a CVE remains unpatched.
(c) Skip validation because the twin is not production.
(d) Fail zero-disruption validation.

### Question 42

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A baggage-handling operator runs Chapter 6 zero-disruption validation. The four checks
are port reachability, orphaned firewall rules, bridge integrity, and critical
infrastructure connectivity. The result is: a critical PLC-to-HMI connection is no
longer reachable. Which validation decision follows?

(a) Fail only if a CVE remains unpatched.
(b) Skip validation because the twin is not production.
(c) Fail zero-disruption validation.
(d) Pass because the BRS delta is negative.

### Question 43

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility runs Chapter 6 zero-disruption validation. The four checks are port
reachability, orphaned firewall rules, bridge integrity, and critical infrastructure
connectivity. The result is: a Docker bridge has a negative or impossible container
count. Which validation decision follows?

(a) Skip validation because the twin is not production.
(b) Fail zero-disruption validation.
(c) Pass because the BRS delta is negative.
(d) Fail only if a CVE remains unpatched.

### Question 44

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

A power cooperative runs Chapter 6 zero-disruption validation. The four checks are port
reachability, orphaned firewall rules, bridge integrity, and critical infrastructure
connectivity. The result is: a service that must remain reachable no longer has an open
port. Which validation decision follows?

(a) Fail zero-disruption validation.
(b) Pass because the BRS delta is negative.
(c) Fail only if a CVE remains unpatched.
(d) Skip validation because the twin is not production.

### Question 45

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A pipeline operator runs Chapter 6 zero-disruption validation. The four checks are port
reachability, orphaned firewall rules, bridge integrity, and critical infrastructure
connectivity. The result is: all checks pass. Which validation decision follows?

(a) Pass because the BRS delta is negative.
(b) Fail only if a CVE remains unpatched.
(c) Skip validation because the twin is not production.
(d) Pass zero-disruption validation.

### Question 46

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A baggage-handling operator asks what a Chapter 6 structural digital twin can and cannot
prove. The stated twin models topology, device profiles, open services, firewall rules,
and service dependencies. It does not replicate physical I/O behavior, packet-level
timing, or vendor firmware state machines. Which claim stays inside that fidelity
boundary?

(a) It can reproduce nanosecond packet timing for every industrial protocol.
(b) It cannot test any remediation because it is only a diagram.
(c) It can screen whether disabling a service or changing a firewall rule breaks modeled dependencies, but it cannot certify physical process safety by itself.
(d) It can certify that a chemical dosing loop remains safe under all physical operating conditions.

### Question 47

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility asks what a Chapter 6 structural digital twin can and cannot prove. The
stated twin models topology, device profiles, open services, firewall rules, and service
dependencies. It does not replicate physical I/O behavior, packet-level timing, or
vendor firmware state machines. Which claim stays inside that fidelity boundary?

(a) It cannot test any remediation because it is only a diagram.
(b) It can screen whether disabling a service or changing a firewall rule breaks modeled dependencies, but it cannot certify physical process safety by itself.
(c) It can certify that a chemical dosing loop remains safe under all physical operating conditions.
(d) It can reproduce nanosecond packet timing for every industrial protocol.

### Question 48

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

A power cooperative asks what a Chapter 6 structural digital twin can and cannot prove.
The stated twin models topology, device profiles, open services, firewall rules, and
service dependencies. It does not replicate physical I/O behavior, packet-level timing,
or vendor firmware state machines. Which claim stays inside that fidelity boundary?

(a) It can screen whether disabling a service or changing a firewall rule breaks modeled dependencies, but it cannot certify physical process safety by itself.
(b) It can certify that a chemical dosing loop remains safe under all physical operating conditions.
(c) It can reproduce nanosecond packet timing for every industrial protocol.
(d) It cannot test any remediation because it is only a diagram.

### Question 49

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A pipeline operator asks what a Chapter 6 structural digital twin can and cannot prove.
The stated twin models topology, device profiles, open services, firewall rules, and
service dependencies. It does not replicate physical I/O behavior, packet-level timing,
or vendor firmware state machines. Which claim stays inside that fidelity boundary?

(a) It can certify that a chemical dosing loop remains safe under all physical operating conditions.
(b) It can reproduce nanosecond packet timing for every industrial protocol.
(c) It cannot test any remediation because it is only a diagram.
(d) It can screen whether disabling a service or changing a firewall rule breaks modeled dependencies, but it cannot certify physical process safety by itself.

### Question 50

**Scenario provenance only (not needed to answer):** OASIS STIX 2.1 standard.

A maritime port authority asks what a Chapter 6 structural digital twin can and cannot
prove. The stated twin models topology, device profiles, open services, firewall rules,
and service dependencies. It does not replicate physical I/O behavior, packet-level
timing, or vendor firmware state machines. Which claim stays inside that fidelity
boundary?

(a) It can reproduce nanosecond packet timing for every industrial protocol.
(b) It cannot test any remediation because it is only a diagram.
(c) It can screen whether disabling a service or changing a firewall rule breaks modeled dependencies, but it cannot certify physical process safety by itself.
(d) It can certify that a chemical dosing loop remains safe under all physical operating conditions.
