Missing DNSSEC Leaves Your Domain Exposed: How Attackers Abuse Unsigned DNS

You may assume your domain is safe simply because it resolves and your website loads correctly. But what most organisations overlook is the path in between. DNS responses travel through networks and systems you don't control. If your zone is not protected with DNSSEC, anyone in that path who can interfere with DNS traffic could change the answers your users receive.

Even though the risks are real, DNSSEC adoption is still low. A recent study of resolver validation in the EU found an average DNSSEC validation rate of 49.4 percent, and globally about 35.4 percent. Meanwhile, ProtocolGuard reports that as recently as October 2024 only about 5 percent of .com domains were signed. That gap means a huge portion of important domains are still exposed.

If your organisation relies on SaaS tools, CDNs or cloud based email services, a forged DNS answer can redirect login screens, send email to an attacker controlled mail server, or silently hijack traffic. DNSSEC does not fix weak passwords or insecure apps, but it does protect the DNS layer itself, which is the foundation for everything that sits above it.

Quick refresher on what DNSSEC really does

DNSSEC does not encrypt DNS traffic. What it adds is integrity and authentication. In classic DNS the sequence is: a client asks its resolver for yourdomain.com., the resolver goes to the DNS hierarchy and gets an answer, then returns it to the client. There is no built in verification that the answer is legitimate.

When DNSSEC is enabled and properly validated: the zone owner signs DNS records using a private key; the public key is published via DNSKEY; the parent zone publishes a DS record linking the chain of trust downward; and validating resolvers check that the RRSIG signatures match the DNSKEY, and that the DNSKEY matches the DS in the parent.

If something does not line up, the resolver treats the answer as bogus rather than returning it to the user. This adds authenticity and integrity to DNS responses and makes tampering much harder.

What no DNSSEC looks like in real life

Cache poisoning and forged answers

Even though DNS resolvers have improved since earlier attacks, if your zone is not signed they still rely on unpredictable transaction IDs, random source ports and timing. An attacker who can observe or guess queries might inject a forged response: fake IP for your portal, fake MX for your email domain or fake NS records pointing your zone to hostile name-servers.

With DNSSEC the signatures would not match and a validating resolver will reject fraudulent data.

Registrar or DNS provider account takeover

DNSSEC will not prevent someone from logging into your registrar or DNS provider account and changing records. But the impact changes significantly. If your zone is unsigned and an attacker gets in, they can silently change NS records, point your zone to a malicious server and publish whatever records they want. Everyone resolves it without warning.

If your zone is signed and DS records exist in the parent, an attacker who cannot produce valid signatures usually breaks the chain. Validating resolvers then fail rather than quietly trust malicious data. Visible failure is far safer than silent compromise.

Man-in-the-middle or interception attacks

On hotel WiFi, corporate proxy networks or ISPs that intercept DNS, a malicious actor could send faster forged DNS answers. Without DNSSEC your users might accept them without noticing anything unusual.

With DNSSEC enabled, answers without valid signatures fail validation on resolvers that check it.

How to check if your domain uses DNSSEC

You don't need any internal access. This can all be done remotely.

Using dig:

dig +dnssec yourdomain.com

Look for RRSIG records and the ad flag in the header if the resolver is validating DNSSEC. For example, a signed zone will show RRSIG in the answer section and the ad flag.

Then check the parent delegation:

dig yourdomain.com DS

If you get an empty answer plus proof (NSEC or NSEC3) of non-existence, your parent zone has no DS record so the chain is broken.

At DNSAudit.io we perform remote checks by: querying the parent for DS records; querying the authoritative zone for DNSKEY and RRSIG; detecting algorithm issues or mismatches; and classifying zones as unsigned, partially configured, properly configured or misconfigured.

Common DNSSEC failure modes

DS record exists but zone is not signed

This happens often when a provider migration leaves the DS record at the registrar but the new provider doesn't sign. Validating resolvers see a broken chain and may return SERVFAIL while non-validating resolvers keep working, causing inconsistent behaviour.

Zone is signed but parent has no DS

In this case the zone is technically signed but the chain of trust from the parent root is incomplete. The wider internet treats the domain as unsigned.

Weak or outdated algorithms

Some zones are signed but use older or deprecated algorithms. They technically support DNSSEC but the level of protection is not as strong as one might assume. According to research, over 4 percent of evaluated domains show DNS misconfigurations and about 75 percent of those were unreachable from a validating resolver.

Why organisations still don't implement DNSSEC

Here are real‐world reasons based on documented studies.

Lack of expertise. Many teams find DNSSEC requires coordination with registrar and DNS provider and ongoing maintenance, and avoid it because they lack experience.

Operational and cost concerns. ProtocolGuard notes that fewer than 5 percent of .com domains are signed, largely due to perceived complexity, fear of outages and limited visible benefit.

Bootstrap and network-effect problems. Research highlights that unless a large portion of domains, resolvers and parent zones adopt DNSSEC, the benefits for a single standalone zone can be limited.

Fear of breakage. Studies found domains with DNSSEC are sometimes misconfigured and unreachable from validating resolvers, which births fear of outages.

Perceived low ROI. Because DNSSEC is invisible to end-users and does not directly block phishing, many security teams deprioritise it.

How to enable DNSSEC without breaking everything

DNSSEC adds a real layer of protection to your domain, but turning it on requires a bit of planning. When every piece lines up, it works smoothly. When something is off, you can break validation for a lot of users. The goal is simple: enable it in a controlled way, confirm that the chain of trust is correct, and keep it maintained over time.

1. Check that your environment supports it

Before you make any changes, confirm that the basics are in place.

• Your DNS provider must support zone signing and proper handling of DNSKEY, RRSIG and NSEC or NSEC3 records.
• Your registrar must allow you to publish a DS record in the parent zone. Without that link, DNSSEC will not function.
• All authoritative name servers must serve the same correctly signed zone. This applies whether you use one provider or several. If you use multiple DNS platforms, make sure they stay in sync and all support DNSSEC in the same way.

2. Roll it out in a safe and predictable way

A good rollout looks like this:

• Generate your keys. You need a Zone Signing Key and a Key Signing Key.
• Sign the zone so it contains the DNSKEY and RRSIG records, plus the NSEC or NSEC3 chain required for proofs of nonexistence.
• Publish the DS record at your registrar so the parent zone can establish trust with your signed zone.
• Turn on DNSSEC in your DNS provider and test it from outside your network. Validating resolvers should resolve your domain without issues.

3. Keep watching it after it is turned on

DNSSEC works well when you maintain it.

• RRSIG records expire, so you need to watch signature lifetimes and make sure new signatures are published before the old ones become invalid.
• Key rollovers must be done carefully. The DS record in the parent zone and the DNSKEY in the child zone must match during the entire rollover period, and TTLs must be respected.
• DNSSEC responses are larger than normal DNS responses. If there are network devices or paths that mishandle EDNS or fragmented packets, you may see resolution problems.
• Any DNS provider change, nameserver change or infrastructure migration must be planned with DNSSEC in mind so the chain of trust does not break during the transition.

4. Know the risks that still remain

Even a well implemented DNSSEC setup has things you need to keep in mind.

• A wrong DS record or a mismatched DNSKEY will cause validation failures for resolvers that enforce DNSSEC.
• A poorly timed key rollover can create a short outage if parent and child records are not aligned while caches are clearing.
• Depending on how your NSEC or NSEC3 chain is configured, it may be possible to enumerate some of your zone contents.
• Complex DNS setups require more coordination to avoid serving inconsistent data, especially when multiple providers or teams are involved.

A detailed step by step guide can be found here: https://dnsaudit.io/docs/dnssec-missing

How DNSAudit.io helps make this simple

DNSAudit.io scans domains remotely for DS records, DNSKEY and RRSIG, classifies the DNSSEC posture as: not configured, partially configured, fully configured or misconfigured. And it provides remediation hints and links to full documentation so your security team can start with the implementation right away.

You can combine DNSSEC status with other DNS security checks (MX/SPF/DKIM/DMARC) and prioritise the domains where unsigned DNS plus risky mail/web posture means highest overall risk.

Click to enlarge: DNSAudit.io showing a DNSSEC not enabled warning with remediation guidance

Practical recommendations

1. Inventory all your domains including sub-domains
2. Prioritise domains with login portals, main sites and email services
3. Enable DNSSEC using managed signing where possible
4. Monitor DNSSEC health especially after DNS or registrar changes

DNSSEC will not replace firewalls, anti-phishing tools or authentication controls but it closes a fundamental gap in the DNS layer. If your domain is critical, signing it is one of those setup tasks that gives long-term value for very little ongoing effort.