When Legitimate DNS Services Accidentally Point to Threat Actor Infrastructure

Security researchers recently uncovered something unsettling: two hostnames belonging to ClouDNS—a legitimate Bulgarian hosting provider—were pointing directly to an IP address controlled by a known threat actor called Prolific Puma.

The hostnames in question, api2.cloudns.net and web2.cloudns.net, were essentially creating a bridge between trusted infrastructure and malicious operations. ClouDNS serves major organizations like Hostway, KIA, and Der Spiegel, which makes this discovery particularly concerning. The good news? When contacted, ClouDNS immediately updated their DNS records to fix the issue.

Why This Matters More Than You'd Think

At first glance, this might seem like a simple misconfiguration. But the implications run deeper than a forgotten DNS record.

When legitimate hostnames point to malicious infrastructure, they become powerful weapons for attackers. Security products that rely on reputation-based filtering might let traffic through simply because the domain looks trustworthy. After all, who would suspect api2.cloudns.net of being dangerous?

Attackers can exploit this in several ways. They might craft phishing emails with links that look completely legitimate—imagine receiving an email that appears to come from a known service provider, with a URL that passes every initial check. Employees and users would have little reason to be suspicious.

The threat extends to more sophisticated attacks too. Cookie-based attacks on authentication systems become easier when you control what appears to be a legitimate subdomain. And here's a kicker: threat actors can even generate SSL certificates for these subdomains, adding another layer of apparent legitimacy to their operations.

The DNS Hygiene Problem Nobody Talks About

Here's what many organizations miss: DNS records are often set up once and then forgotten. A developer might configure a hostname for testing, a migration might leave old records in place, or infrastructure changes might orphan certain DNS entries entirely.

This creates an opportunity window for attackers. If those IP addresses get reassigned or if threat actors somehow gain control of the destination infrastructure, suddenly your legitimate domain is pointing somewhere you definitely don't want it to go.

👉 Managing DNS records across multiple domains and ensuring they point to the right infrastructure requires reliable DNS hosting solutions

Regular DNS audits should be part of every organization's security routine. Walk through your DNS settings and ask: Do we still use this? Do we control the IP address this points to? If you can't answer with certainty, that's a red flag worth investigating.

What Organizations Should Do Right Now

Start by conducting a comprehensive review of your DNS records. Look for hostnames pointing to IP addresses your team doesn't recognize or can't verify as actively used infrastructure.

Pay special attention to older subdomains—those api-test, staging, or legacy hostnames that might have been set up years ago. These forgotten corners of your DNS configuration are exactly where problems like this hide.

The good news is that checking DNS configurations doesn't require expensive enterprise tools. Free security platforms make it straightforward to examine your DNS settings and spot potential issues before they become security incidents.

👉 Implementing proper DNS management with features like monitoring and alerting helps catch these configuration drift issues early

The Bigger Picture: Infrastructure Vulnerabilities

While no malicious activity was detected in this specific case, the incident highlights a broader vulnerability pattern. Prolific Puma, the threat actor involved, maintains over a thousand active domains according to security researchers who track their operations.

The challenging part about tracking threat actors like Prolific Puma is that their infrastructure constantly evolves. New domains appear, old ones get abandoned, and tactics shift as defenders adapt. This cat-and-mouse game means yesterday's threat intelligence might not protect you tomorrow.

Organizations need to think proactively rather than reactively. Instead of only blocking known bad domains, consider how attackers might abuse your own infrastructure. What if your DNS records became part of someone else's attack chain? What safeguards do you have in place?

Moving Beyond Traditional IOCs

Traditional cybersecurity focuses heavily on Indicators of Compromise—the digital breadcrumbs left after an attack happens. But what if you could spot the warning signs before the attack even starts?

This is where behavioral threat modeling comes into play. Rather than waiting for a domain to be used maliciously, security teams can identify suspicious patterns in how infrastructure is being set up and configured. Clusters of newly registered domains, unusual DNS patterns, or infrastructure that mimics legitimate services—these all serve as early warning signals.

The ClouDNS incident demonstrates why this proactive approach matters. The hostnames were discovered before any attack occurred, giving defenders a chance to fix the vulnerability rather than respond to an active breach.

Practical Steps for Better DNS Security

Make DNS hygiene a regular practice, not a one-time project. Set up quarterly reviews where you examine your DNS records and verify everything is pointing where it should. Document why each record exists and who's responsible for it.

Implement monitoring for DNS changes. You should know immediately if a DNS record gets modified, especially for critical production systems. Many security incidents start with subtle infrastructure changes that go unnoticed until it's too late.

Consider implementing DNS security features like DNSSEC to protect against certain types of attacks. While it won't prevent misconfiguration issues like the one ClouDNS experienced, it adds another layer of defense against DNS-based attacks.

Keep your DNS provider selection criteria focused on security. Look for providers that offer audit logs, change notifications, and security monitoring features. The cheapest option isn't always the best when your organization's security depends on reliable DNS infrastructure.

The Takeaway

The ClouDNS incident serves as a reminder that security vulnerabilities don't always come from sophisticated zero-day exploits or advanced persistent threats. Sometimes the risk comes from something as mundane as a forgotten DNS record pointing to the wrong place.

Organizations that take DNS security seriously—through regular audits, proper documentation, and proactive monitoring—significantly reduce their attack surface. It's not glamorous work, but it's the kind of foundational security hygiene that prevents embarrassing incidents and real security breaches.

Check your DNS records today. You might be surprised what you find.