Identify routing and name-resolution attack surfaces.
Explain DNS integrity, availability, and confidentiality concerns.
Design administrative controls for network changes.
Routing decides where packets travel; DNS maps names to records. Attackers may redirect traffic, poison caches, hijack routes, enumerate internal names, or exhaust resolvers. Security requires authenticated administration, change review, protected resolver access, monitoring, and appropriate DNSSEC or encrypted transport choices.
client -> trusted resolver -> authoritative service
validate response, scope recursion, log unusual volume or record changes
Availability and integrity are distinct: a resolver outage prevents access, while a forged record sends users to the wrong destination. Do not confuse encrypted DNS transport with proof that a record is authoritative; each protects a different part of the path.
Exercises
Threat-model an enterprise recursive resolver.
Define controls for unauthorized DNS record changes.
Explain how a route change could affect confidentiality.
Self-check
What does DNS integrity protect?
Why restrict recursion?
Who should approve routing changes?
Self-Check Quiz
1. What can a forged DNS record do?
AnswerRedirect clients to an attacker-controlled or incorrect destination, affecting integrity and confidentiality.
2. Does encrypted DNS prove a record is correct?
AnswerNo. Transport encryption protects the query path; authenticity requires appropriate validation and trusted resolution.
Homework
Design secure DNS administration for a multi-site enterprise.
Define monitoring for record tampering and resolver abuse.
Write an emergency response for a suspected DNS hijack.
Sample answerRestrict record changes with MFA, role separation, approvals, protected provider accounts, and audit logs. Response includes confirming authoritative records, preserving evidence, rotating compromised credentials, correcting records, lowering exposure, notifying affected users, and monitoring caches.