SY0-401 Free Dumps Study Materials
Question 22: Users at a company report that a popular news website keeps taking them to a web page
with derogatory content. This is an example of which of the following?
A. Evil twin
B. DNS poisoning
C. Vishing
D. Session hijacking
Correct Answer: B
Explanation:
DNS spoofing (or DNS cache poisoning) is a computer hacking attack, whereby data is introduced into
a Domain Name System (DNS) resolver's cache, causing the name server to return an incorrect IP
address, diverting traffic to the attacker's computer (or any other computer).
A domain name system server translates a human-readable domain name (such as example.com)
into a numerical IP address that is used to route communications between nodes. Normally if the
server doesn't know a requested translation it will ask another server, and the process continues
recursively. To increase performance, a server will typically remember (cache) these translations for a
certain amount of time, so that, if it receives another request for the same translation, it can reply
without having to ask the other server again.
When a DNS server has received a false translation and caches it for performance optimization, it is
considered poisoned, and it supplies the false data to clients. If a DNS server is poisoned, it may
return an incorrect IP address, diverting traffic to another computer (in this case, the server hosting
the web page with derogatory content).