AI Agents and the Resurgence of ‘Dangling DNS’: A Growing Cybersecurity Risk
A silent threat lurks within the infrastructure of countless organizations: abandoned digital footprints known as “dangling DNS” records. These inactive DNS entries, pointing to services and resources that no longer exist, have long been a minor security concern, often exploited for phishing campaigns. However, the rise of artificial intelligence and automated agents is dramatically amplifying the danger, transforming a manageable nuisance into a potentially catastrophic vulnerability. The problem isn’t new, but the stakes have never been higher.
Experts emphasize this isn’t a vulnerability *created* by AI, but rather one significantly *exacerbated* by it. “This is a long-running cloud hygiene issue,” explains Constellation Research analyst Chirag Mehta. “More automation, more integrations, and more agents that browse and act can turn a small DNS oversight into a higher-leverage control point than it used to be.”
The Anatomy of a Dangling DNS Attack
<p>Imagine a company previously hosted an analytics dashboard at <code>analytics.mycompany.com</code>, pointing to an AWS bucket or an Azure app service like <code>analytics.azurewebsites.net</code>. When that service is decommissioned, the DNS record often remains active. An attacker, recognizing this opportunity, can spin up their own service at the same address – <code>analytics.azurewebsites.net</code> – effectively hijacking incoming traffic.</p>
<p>This isn’t simply about redirecting users to a malicious website. The attacker can create a seemingly legitimate page, mirroring the original content while embedding hidden prompts within the HTML, SVG metadata, or other invisible elements. These prompts are designed to be interpreted as legitimate instructions by AI agents. The result? An attacker gains access to everything the agent has permission to access, potentially exfiltrating sensitive data or initiating unauthorized actions.</p>
<p>Akamai Technologies has identified dangling DNS as “the most overlooked attack surface in the AI era,” detailing how it can function as an “automated data exfiltration pipeline” in a recent security post. <a href="https://www.akamai.com/blog/security/dangling-dns-most-overlooked-attack-surface-ai-era">Learn more about Akamai’s findings here</a>.</p>
<p>“Infrastructure or code that is left operational but not maintained and monitored is a classic attack vector for cyber criminals,” says <a href="https://www.linkedin.com/in/steve-winterfeld/">Steve Winterfeld</a>, advisory CISO at Akamai. “And this issue is quickly climbing to the top of the list to address.” Akamai has responded by adding new capabilities to its DNS security suite specifically to combat this threat.</p>
<h2>The Scale of the Problem: Millions of Requests to Abandoned Resources</h2>
<p>The prevalence of dangling DNS records is staggering. Last year, Watchtowr discovered 150 abandoned S3 buckets used in commercial and open-source software, government projects, and infrastructure pipelines. After registering these buckets, they observed over eight million requests in just two months for software updates, binaries, and virtual machine images. <a href="https://labs.watchtowr.com/8-million-requests-later-we-made-the-solarwinds-supply-chain-attack-look-amateur/">Read the full Watchtowr report</a>.</p>
<p>This isn’t a niche issue. Security firm Sentinel One alerted its clients to over 1,250 instances of subdomain takeover risk linked to dangling DNS in the past year. Silent Push found that a single customer had over 2,000 exploitable DNS records requiring immediate remediation. <a href="https://www.sentinelone.com/blog/re-assessing-risk-subdomain-takeovers-as-supply-chain-attacks/">Sentinel One’s analysis</a> and <a href="https://www.silentpush.com/blog/subdomain-takeovers-and-dangling-dns-exploits/">Silent Push’s report</a> underscore the widespread nature of this vulnerability.</p>
<p>Dangling DNS and subdomain takeovers have been exploited for over a decade, according to <a href="https://www.linkedin.com/in/avinashrajeev/">Avinash Rajeev</a>, leader of PwC’s cyber, data and tech risk platform. “It’s not a rare or highly technical edge case.”</p>
<div style="background-color:#fffbe6; border-left:5px solid #ffc107; padding:15px; margin:20px 0;"><strong>Pro Tip:</strong> Regularly audit your DNS records and implement automated tools to identify and remove dangling entries. Prioritize this as a core component of your cloud hygiene strategy.</div>
<h2>AI Amplifies the Threat: Automation and Scale</h2>
<p>The integration of AI into cyberattacks further complicates the landscape. Attackers can now leverage AI to identify vulnerable DNS records at scale, automating the process of discovery and exploitation. Forrester analyst <a href="https://www.linkedin.com/in/jamesplouffe/">James Plouffe</a> notes, “AI can grind in a way that humans can’t, which really reduces the opportunity cost for attackers looking for dangling DNS records to exploit.”</p>
<p>Once identified, AI agents can also automate the provisioning of malicious infrastructure, expanding the attack surface exponentially. This allows adversaries to cast a much wider net with minimal effort.</p>
<p>Furthermore, the emergence of prompt injection attacks, recently highlighted by Palo Alto’s Unit42, adds another layer of complexity. <a href="https://unit42.paloaltonetworks.com/ai-agent-prompt-injection/">Their research</a> demonstrates real-world instances of indirect prompt injections targeting AI agents and LLM-based systems.</p>
<p>Are your organization’s AI agents adequately protected against malicious prompts originating from compromised DNS records? What safeguards are in place to prevent unauthorized access and data exfiltration?</p>Mitigating the Risk: A Two-Pronged Approach
Addressing this challenge requires a comprehensive strategy focused on both DNS hygiene and AI agent security. Plouffe emphasizes that many DNS service providers already offer tools to detect and clean up dangling records. “Those features just need to be enabled and operationalized.”
Simultaneously, organizations must implement robust guardrails for their AI agents, enabling them to evaluate the semantic intent of prompts and restrict access to untrusted web content. This includes validating the source of information and limiting the agent’s ability to execute actions based on potentially compromised data.
As Rajeev of PwC concludes, “Dangling DNS is not a new class of vulnerability, but it is a preventable one. As digital ecosystems grow, especially with AI, foundational cyber hygiene becomes even more important. Small gaps can scale quickly.”
Frequently Asked Questions About Dangling DNS and AI Security
What is a dangling DNS record?
A dangling DNS record is an outdated DNS entry that points to a resource (like a server or website) that no longer exists. It’s essentially a broken link in the internet’s address book.
How does dangling DNS impact AI agents?
AI agents can be tricked by dangling DNS records into accessing malicious content or executing unauthorized actions if attackers hijack the abandoned DNS entry and embed harmful prompts.
Is dangling DNS a new security threat?
While not new, the threat of dangling DNS has been significantly amplified by the increasing use of AI agents and automated systems, allowing attackers to exploit vulnerabilities at a much larger scale.
What steps can organizations take to prevent dangling DNS?
Organizations should regularly audit their DNS records, automate the removal of inactive entries, and implement robust security measures for their AI agents to prevent prompt injection attacks.
What is prompt injection and how does it relate to dangling DNS?
Prompt injection is a technique where attackers manipulate the prompts given to AI agents to cause them to perform unintended actions. Dangling DNS can be used to deliver these malicious prompts through hijacked websites.
Share this critical insight with your network and join the conversation in the comments below. How is your organization addressing the growing threat of dangling DNS in the age of AI?
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