Which of the following is most likely to cause the greatest amount of disruption on a router? (Select the best answer.)
- a Trojan horse
- a worm
- a DDoS attack
Of the available choices, a Distributed Denial of Service (DDoS) attack is most likely to cause the greatest amount of disruption on a router. A DDoS attack is a coordinated Denial of Service (DoS) attack that uses multiple attackers to target a single host. For example, a large number of zombie hosts in a botnet could flood a target device with packets. Because the flood of packets originates from multiple hosts and typically targets public services, such as the web service, the target device might not detect the attack. If enough packets are sent to the target device within a short period of time, the target will be unable to respond to legitimate packets because it is waiting for a response to each of the requests originated by the attacker.
A Trojan horse does not cause the greatest amount of disruption on a router. A Trojan horse is a type of malicious software that appears to be legitimate software. Because a Trojan horse appears to be legitimate, users often load the Trojan horse unknowingly. The Trojan horse can then affect the computer in several ways. Some Trojan horses cause advertising popups to be displayed intermittently. Other Trojan horses can cause more harm by deleting or damaging data. Because a router runs only Ciscoproprietary software, there is little chance that a Trojan horse could inadvertently be installed.
Likewise, a worm does not cause the greatest amount of disruption on a router. A worm is a specific type of standalone, malicious software that has the ability to selfpropagate. A worm typically exploits vulnerabilities in an operating system (OS) to compromise a computer and to install copies of itself onto the infected device. Because a router runs only Ciscoproprietary software, there is little chance that a worm could exploit a vulnerability in its OS and infect the router. Although excessive network traffic caused by worm propagation could negatively affect the performance of a router, it is unlikely that this traffic would be comparable to the impact of a DDoS attack.
Spyware does not cause the greatest amount of disruption on a router. Spyware is a type of unwanted software that can record a user’s actions and personal information. Because a router runs only Ciscoproprietary software, there is little chance that spyware could inadvertently be installed.