DNS poisoning in Computer Networks - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is DNS poisoning?

Which of the following best describes DNS poisoning?

A A method to speed up DNS queries by caching results locally.

B A process of updating DNS records to reflect new IP addresses.

C A technique to encrypt DNS requests for privacy.

D An attack that corrupts the DNS cache to redirect users to malicious sites.

💡 Hint

Think about what happens when DNS information is changed to mislead users.

DNS poisoning involves corrupting the DNS cache so that users are redirected to fake or harmful websites instead of the intended ones.

📋 Factual

intermediate

Common target of DNS poisoning attacks

Which part of the DNS system is most commonly targeted in DNS poisoning attacks?

A DNS resolver cache

B Authoritative DNS server database

C Root DNS servers

D Local hosts file on user computers

💡 Hint

Attackers often try to trick the system that answers queries for users quickly.

The DNS resolver cache stores recent DNS query results and is commonly targeted because poisoning it affects many users quickly.

🔍 Analysis

advanced

Impact of DNS poisoning on users

What is the most likely outcome for a user whose DNS cache has been poisoned?

A Their device will automatically update DNS settings to fix the issue.

B Their internet connection will be completely blocked.

C They will be redirected to fraudulent websites without knowing it.

D They will receive a warning message from their browser about DNS errors.

💡 Hint

Consider what happens when DNS points to wrong IP addresses.

When DNS cache is poisoned, users unknowingly visit fake websites that can steal information or spread malware.

❓ Comparison

advanced

Difference between DNS poisoning and DNS spoofing

Which statement correctly distinguishes DNS poisoning from DNS spoofing?

A DNS poisoning encrypts DNS data; DNS spoofing decrypts it.

B DNS poisoning corrupts cached DNS data; DNS spoofing involves sending fake DNS responses during a query.

C DNS poisoning happens only on servers; DNS spoofing happens only on clients.

D DNS poisoning is a defensive technique; DNS spoofing is an attack.

💡 Hint

Think about when the fake DNS information is introduced in each attack.

DNS poisoning changes stored DNS data to mislead future queries, while DNS spoofing sends fake DNS replies during a live query to trick the user immediately.

❓ Reasoning

expert

Why DNSSEC helps prevent DNS poisoning

How does DNSSEC help protect against DNS poisoning attacks?

A By digitally signing DNS data to verify its authenticity before use.

B By encrypting all DNS queries to hide them from attackers.

C By blocking all DNS requests from unknown IP addresses.

D By automatically clearing the DNS cache every minute.

💡 Hint

Consider how DNSSEC ensures the DNS data is trustworthy.

DNSSEC adds digital signatures to DNS data so that resolvers can check if the data is genuine and not tampered with, preventing poisoning.