Effective CISSP Questions

Your company is a well-known cloud services provider. You received one day, tons of complaints from customers about a sudden drop in network performance for hours. An incident investigation is initiated and finally concluded that misconfigured routing between autonomous systems from a peer service provider is the root cause. Which of the following is the most probable threat scenario?
A. The peer service provider causes a routing loop between neighbors without a metric that counts to infinity.
B. The peer service provider sends wrong routing entries with non-standard compliant interior gateway protocols.
C. The peer service provider redirects the traffic to its networks intentionally or unintentionally.
D. The peer service provider overloads the voice and data traffic by Signaling System No. 7 (SS7).

Kindly be reminded that the suggested answer is for your reference only. It doesn’t matter whether you have the right or wrong answer. What really matters is your reasoning process and justifications.

My suggested answer is C. The peer service provider redirects the traffic to its networks intentionally or unintentionally.

Exterior Gateway Protocols (EGP)

Routing between service providers typically uses exterior gateway protocols (EGP); BGP is one of the most common EGPs. “Autonomous systems (AS)” implies the use of EGP and BGP. Commonly, peer service provider redirects or hijacks internet traffic intentionally or unintentionally. There are many real-life examples of traffic hijacking by China’s misconfiguratio of BGP.

Interior Gateway Protocols (IGP)

A routing loop, typically happening in distance vector protocols, is a situation where a packet keeps getting routed between two or more routers because of problems in the routing table. It can have a devastating effect on a network, resulting in degraded network performance or even a network downtime. Maximum Hop Count, Split Horizon, Route Poisoning/Poison Reverse, and Hold Downs are common mechanisms to prevent routing loop. The hop count should be imposed a maximum value instead of counting to infinity, which causes the routing loop.

Non-standard compliant protocols may cause the problem, but the option states it is an interior gateway protocols (IGP). Service providers use EGPs to route between Autonomous systems (AS).

Signaling System No. 7 (SS7) is an out of band signaling protocol for telecommunication.





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