DoS attacks can cause harm by ________.

• A. Stopping a critical service
• B. Slowly degrading services over a period of time
• C. Neither A nor B
• D. Both A and B

Answer: (D)

The core idea is that DoS attacks target availability by overwhelming a system so legitimate users can’t access it. This can happen in two ways: one is to stop a critical service entirely, cutting off access at once; the other is to keep applying pressure that degrades performance over time, leading to higher latency, timeouts, and failed operations. Both outcomes harm users and operations, and many attacks can produce either immediate outage or sustained degradation (or both). Different DoS strategies—flooding bandwidth to crash services or exhausting application and resource limits to slow responses—illustrate why this harm can take multiple forms. That’s why the option encompassing both stopping and degrading correctly captures how DoS attacks cause damage.