The Hidden Threat: Abandoned Asset Vulnerabilities

Introduction

On 29 October 2025, I had a great experience attending Infoblox Exchange 2025 today at Conference Center at Waltham Woods.

It was an insightful and energizing event focused on the future of networking, security, and multi-cloud infrastructure and how AI is reshaping these technologies. We heard from outstanding speakers from Infoblox and across the industry who shared valuable insights on emerging trends.

One of my favorite parts was the hands-on labs on the Infoblox Portal, where we explored how to build full visibility across AWS and Azure environments. It was exciting to see how advanced tools can unify visibility and simplify control in complex cloud ecosystems.

In this article, I want to share an important vulnerability that we need to be aware of as cloud engineers and developers. This is not a paid article and Infoblox is only one example from the real world. You can use any software that helps you solve these problems.

In the age of cloud computing and rapid infrastructure deployment, developers spin up and tear down resources daily, such as domains, cloud instances, load balancers, IPs, and DNS records. But in this fast‑moving environment, abandoned assets can quietly become a hacker’s playground.

Among the most dangerous, yet often overlooked, are dangling CNAME records and recovered IP vulnerabilities. These seemingly harmless leftovers can open doors for domain hijacking, phishing, malware distribution, and data leaks.

What Are Abandoned Asset Vulnerabilities?

An abandoned asset is any digital resource or configuration that remains publicly accessible but is no longer controlled by your organization. Examples include:

• Unused DNS records (e.g., CNAME or A records pointing to deleted services)
• Released or expired cloud IPs
• Unmaintained storage buckets or containers
• Old application subdomains

Attackers actively scan the internet for such orphaned assets. Once found, they can reclaim or spoof them to impersonate your brand or compromise users.

The Dangling CNAME Problem

A CNAME (Canonical Name) record maps one domain name to another. For example:

docs.example.com → mydocs‑hosting.azurewebsites.net

If you delete the target service (e.g., the Azure Web App) but forget to remove the CNAME from DNS, the record still points to that external platform. Now, an attacker who creates a new Azure Web App with the same subdomain (mydocs‑hosting) can claim your old CNAME target, effectively taking control of docs.example.com.

Related Risks

• Host phishing pages on your legitimate subdomain.
• Bypass email or SPF filters if the domain is trusted.
• Deliver malware under your brand’s domain.
• Damage SEO and trust reputation.

Real‑World Example

A large organisation left a CNAME pointing to a deleted Amazon S3 bucket. Attackers claimed the bucket and hosted a phishing campaign using the company’s subdomain, bypassing many corporate email filters.
According to Infoblox’s threat‑intelligence blog post:

“A malicious actor can now use their account … to create new content … gaining control of the content that the alias points to.” (blogs.infoblox.com)

Recovered IP Vulnerability

Cloud providers like Amazon Web Services, Microsoft Azure, and Google Cloud recycle public IP addresses after they’re released. If your DNS A record still points to an old IP after you shut down the service, the new tenant of that IP could intercept or impersonate your domain.

For example:

app.example.com → 52.14.123.45

If you deleted the EC2 instance but forgot to remove the DNS record, another AWS customer might get that same IP later. If they host a web server, users visiting app.example.com will now land on their server — not yours.

Risks

• Session hijacking if cached authentication cookies are reused.
• Credential theft through spoofed login portals.
• Sensitive data leaks via APIs or integrations still targeting the domain.

Why These Issues Are Increasing

• Complex cloud environments – Multi‑cloud, multi‑account setups increase the risk of DNS misconfigurations.
• Frequent CI/CD changes – Automated deployments often create and destroy resources rapidly.
• Poor asset tracking – DNS changes may be manual and unmonitored.
• Short‑lived resources – Temporary test environments and sandboxed domains are easy to forget.

How to Detect and Prevent Abandoned Asset Vulnerabilities

Detection Strategies

Regular DNS Audits

• Identify CNAME, A, and NS records pointing to decommissioned services.
• Compare against your active infrastructure inventory.

Automated Cloud Asset Discovery

• Use cloud‑provider tools like AWS Config, Azure Resource Graph, or GCP Cloud Asset Inventory.
• Detect inconsistencies between DNS and actual cloud state.

External Attack Surface Monitoring (EASM)

• Tools like Shodan, Censys, or security platforms (e.g., Detectify, Intruder.io) can find dangling records.
• Integrate findings into your vulnerability management pipeline.

DNS Zone Hygiene Tools

Use open‑source scanners such as:

• dnstwist
• subjack
• dnscan

These help detect subdomains pointing to deprecated services (dangling CNAMEs) or mis‑pointed hosts.

Prevention Practices

• Automate DNS cleanup as part of your resource deletion workflows.
• Use managed DNS services with lifecycle tracking (e.g., AWS Route 53, Azure DNS).
• Implement tagging and asset ownership policies in the cloud.
• Monitor for domain takeovers continuously using CI/CD‑integrated scanners.

How Infoblox Software Helps Mitigate These Risks

When it comes to mitigating the threats of abandoned assets (like dangling CNAMEs or recovered IPs), several Infoblox products stand out:

Infoblox Universal Asset Insights™

Automates network discovery and analysis of assets across hybrid and multi‑cloud environments.
Key benefits for abandoned‑asset risk:

• Identifies stale DNS records and disconnected/inactive devices.
• Helps discover assets you may have forgotten (dangling DNS, recycled IPs).
• Correlates DNS, DHCP, IPAM data – giving a full picture of active vs inactive resources.

Infoblox Threat Defense™

A DNS‑layer security solution that blocks malicious activity at query time.
Why it helps:

• If a dangling CNAME is claimed by an attacker, Threat Defense can block traffic to that hijacked domain.
• Reduces the “blast radius” of hijacked assets.
• Adds DNS‑layer control over domain resolution.

Infoblox Universal DDI™ Product Suite

Unifies DNS, DHCP and IPAM into one platform.
Benefits for abandoned‑asset mitigation:

• Tracks IPs in use vs released — reducing recovered‑IP risk.
• Unifies DNS/DHCP/IPAM hygiene across hybrid environments.
• Automates cleanup when decommissioning services.

Practical Usage Approach

1. Use Universal Asset Insights to identify unused DNS and stale IPs.
2. Automate DNS/DHCP/IPAM cleanup through Universal DDI workflows.
3. Deploy Threat Defense to block malicious domain resolutions.
4. Integrate results into your vulnerability management and incident response.

Building a Secure Cloud Hygiene Culture

The most secure teams adopt a “zero‑abandonment policy”, where every resource is accounted for from creation to decommission. Regular DNS audits, automated asset management, and awareness training help prevent costly security incidents.

Key Takeaways

Final Thoughts

Abandoned asset vulnerabilities are low‑effort for attackers but high‑impact for organisations. Every unmonitored DNS record or stale IP is a potential open door into your infrastructure.

Securing your digital footprint isn’t just about firewalls and encryption — it starts with cleaning up what you’ve left behind, and using tools to give you visibility, control and defence.