Stop DNS Hijacking: AI Signals You Can Act On

Most security teams spend hours hardening endpoints and tightening identity controls—then leave DNS as “someone else’s problem.” Attackers love that.

DNS infrastructure hijacking is one of the cleanest ways to steal credentials, siphon email, and run man-in-the-middle attacks without tripping the alarms your SOC watches all day. The CISA advisory on a global DNS hijacking campaign lays out the uncomfortable truth: if an attacker gets access to the account that changes DNS records, they can quietly reroute your business.

Here’s the part I care about in 2025: DNS hijacking is exactly the kind of threat AI can spot early—not by “being smart,” but by doing something humans can’t do well at scale: continuously baselining normal DNS behavior and flagging tiny, meaningful anomalies in real time.

DNS infrastructure hijacking: what actually happens

DNS hijacking succeeds when attackers change where your domains resolve, using valid access. This isn’t a noisy exploit. It’s often a small configuration change made by someone who appears authorized.

CISA described a simple chain that still holds up:

1. Credential compromise for an account that can modify DNS (registrar, DNS host, or internal DNS management tooling).
2. Record manipulation—commonly A, MX, or NS records—pointing traffic to attacker-controlled systems.
3. Certificate abuse—because the attacker controls DNS responses, they can obtain valid TLS certificates for your domain, enabling convincing interception.

This matters because it turns DNS into a steering wheel. The attacker can redirect:

• Web logins (SSO portals, VPN pages, payroll, customer portals)
• Email (MX changes) for silent interception or fraud
• API traffic and service-to-service calls that depend on DNS

DNS hijacking is a “trust inversion” attack: your users do everything right, and still end up at the wrong destination.

Why DNS hijacking is so hard to detect

Most organizations don’t monitor DNS changes like they monitor endpoint changes. Even when they do, the signals are scattered across registrar logs, DNS provider audit trails, certificate transparency events, and passive DNS telemetry.

And the attacker doesn’t need to keep the redirect in place forever. A short window can be enough to:

• harvest passwords
• steal session cookies
• capture email authentication handshakes
• mint certificates that remain usable after the redirect ends

That “risk that persists beyond the period of traffic redirection” is the sleeper problem. If a fraudulent cert exists, you’ve got cleanup to do even after DNS looks normal.

The real blast radius: web, mail, and internal services

DNS hijacking isn’t just about sending users to a fake login page. The most damaging cases combine traffic redirection with selective forwarding.

Web traffic: the invisible man-in-the-middle

With a valid certificate, an attacker can run a proxy that:

• terminates TLS using a legit cert
• inspects credentials or MFA prompts
• forwards requests to the real site to keep the victim unaware

If you’re thinking “but we have MFA,” good. Now consider:

• MFA fatigue attacks paired with a hijacked portal
• session token theft after successful login
• OAuth consent prompts redirected to attacker-controlled endpoints

DNS hijacking doesn’t beat MFA directly—it sidesteps the assumptions around where the user is connecting.

Email traffic: MX records as a CFO fraud factory

Changing MX records can redirect inbound email. Even short-lived interception enables:

• invoice manipulation
• password reset theft
• BEC-style pretexting with authentic thread context

It’s especially dangerous in December: finance teams are closing books, vendors are sending final invoices, and people are rushing. Attackers time infrastructure attacks for moments when verification habits slip.

Internal and hybrid services: the quietest failure mode

A lot of internal tooling still relies on DNS: VPN concentrators, Git, ticketing, internal dashboards, legacy apps. In hybrid environments, split-horizon DNS and multiple resolvers can hide changes for days.

The most common outcome isn’t “total compromise.” It’s worse: partial compromise that’s hard to prove.

Mitigations that still work (and what most teams miss)

If you can’t prevent DNS hijacking 100%, you can make it loud and short-lived. CISA’s mitigations are the right foundation. The gap is execution.

Lock down the places DNS can be changed

Start with the uncomfortable inventory:

• Domain registrar accounts
• DNS hosting provider accounts
• Any internal DNS management portals
• CI/CD pipelines or IaC repos that push DNS updates

Then do the basics aggressively:

• Reset and rotate passwords for every account with DNS change privileges
• Enforce phishing-resistant MFA (FIDO2/WebAuthn where possible) on registrar and DNS provider accounts
• Minimize who can change DNS (role-based access, break-glass accounts, approval workflows)

Here’s what teams miss: MFA on the DNS provider is not enough if the attacker can hijack the email account used for password resets. Your registrar security is only as strong as your recovery paths.

Audit DNS records like production code

Treat DNS as critical configuration:

• Baseline all public DNS records (A, AAAA, CNAME, TXT, MX, NS)
• Alert on any record change outside planned windows
• Require ticket references or change IDs for updates

A practical standard I’ve seen work: every DNS change should be attributable to a person, a system identity, and a business reason.

Hunt for fraudulent certificates

If an attacker can steer DNS, they can request certificates. Your response plan should include:

• monitoring for newly issued certificates for your domains
• verifying issuance was authorized
• revoking fraudulent certificates quickly

Even if you can’t automate revocation end-to-end, you can automate detection and triage.

Where AI helps most: early detection and faster containment

AI is strongest when it watches for “small, rare, and risky” changes across many systems. DNS hijacking is a perfect fit because legitimate changes are infrequent—and anomalies stand out when you baseline properly.

AI signals that often catch DNS hijacking early

A good AI-assisted monitoring program correlates multiple weak signals into a strong alert. Examples:

• Registrar login anomalies: new device, new geo, impossible travel, unusual time-of-day
• DNS record drift: sudden changes to A, MX, or NS records that deviate from known-good patterns
• Name server changes: especially high-risk because they can delegate control to attacker infrastructure
• Certificate issuance anomalies: a certificate issued for a subdomain that never had one, or issued by an unexpected CA
• Traffic pattern shifts: spikes in TLS handshakes, odd HTTP response codes, new ASN/hosting providers receiving your traffic

Individually, these are “interesting.” Together, they’re an incident.

Why “rules-only” monitoring is fragile

Rules catch obvious problems: “alert if NS changes.” Attackers don’t need to be obvious.

AI models (even simple ones) can baseline:

• typical change frequency per domain
• expected TTL ranges
• normal hosting/provider ASNs
• common certificate authorities used by your org

Then they flag deviations with context.

The win isn’t magical prediction. The win is fewer blind spots and faster triage.

A practical AI workflow for DNS defense

If you want something your team can actually run, aim for this pipeline:

1. Collect: registrar audit logs, DNS provider change logs, certificate issuance events, passive DNS, web/email telemetry
2. Baseline: learn “normal” per domain and per record type (who changes what, how often, and where it points)
3. Score: assign risk scores to changes (NS change + new ASN + after-hours = high)
4. Automate response (where safe):
   • temporarily lock registrar
   • pause automated DNS deployments
   • force step-up authentication for DNS admins
5. Human confirmation: quick approval/deny loop with on-call

This is where lead-worthy value shows up: teams don’t need another dashboard. They need an AI-assisted system that turns DNS into an alertable surface the same way EDR turned endpoints into one.

“People also ask” answers your SOC will need

How do you know if your domain has been hijacked?

You look for DNS record changes you didn’t authorize, unexpected certificates, and traffic shifting to unfamiliar infrastructure. If you only check one, check certificate issuance plus DNS change logs.

Can DNS hijacking happen even if our web app is secure?

Yes. DNS hijacking attacks the path to your web app, not the code. A perfectly secure app can still have users redirected to an attacker-controlled proxy.

What’s the fastest containment move?

Regain control of registrar and DNS accounts first, then revert DNS records to known-good values, then hunt and revoke fraudulent certificates. If you don’t lock the change plane, attackers can flip it back.

Is DNSSEC the answer?

DNSSEC helps protect against certain tampering scenarios, but it doesn’t fix the core issue highlighted by CISA: if attackers use compromised credentials to change authoritative records legitimately, DNSSEC will happily sign and serve the “new” truth. DNSSEC is valuable, but it’s not a substitute for securing registrar access and monitoring changes.

A DNS hijacking response checklist (printable and blunt)

If you suspect DNS infrastructure hijacking, do these in order:

1. Lock down the registrar: reset passwords, enforce phishing-resistant MFA, review account recovery settings
2. Freeze DNS changes: pause deployments and restrict privileges to a small break-glass group
3. Export current DNS zone and compare to last known-good baseline
4. Revert records (A, MX, NS) to known-good values
5. Search for newly issued certificates for your domains and revoke the unauthorized ones
6. Check email security controls: SPF/DKIM/DMARC alignment and any suspicious forwarding/routing
7. Review logs for initial access: phishing, credential stuffing, session theft, admin account compromise
8. Add detections: alert on high-risk record changes, registrar logins, and certificate issuance going forward

If your team can’t do steps 1–4 inside a single on-call shift, that’s the operational gap to fix.

DNS hijacking is a signal problem—and AI is built for signal problems

DNS infrastructure hijacking keeps working because it sits between teams: identity owns accounts, network owns DNS, app teams own uptime, and security owns the incident after the damage is done.

The better approach is treating DNS like a monitored, scored, and automated control plane. AI-powered detection is the glue: it correlates registrar access, DNS change events, certificate issuance, and traffic anomalies into a single story your SOC can act on.

If you’re tightening defenses going into 2026 planning, put DNS on the list. Not as a compliance item—as an attack path that can undo your hard work everywhere else. When your AI detections can answer “who changed DNS, where did it point, what certs appeared, and what traffic moved” in minutes, DNS hijacking turns from a nightmare into a contained incident.

Where would a DNS hijack hurt you most: customer login, email, or internal services—and do you have real-time visibility on that path today?