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Cloud Recon: How to find exposed cloud assets that work?

Date

May 16, 2023

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Cloud Recon: How to find exposed cloud assets that work?

Hey there, fellow bug hunters! ⚡ In 2025, cloud adoption is at an all-time high—and so are the bounties for cloud misconfigurations. But with more hunters chasing the same targets, you need modern and innovative recon techniques to stand out and land those big payouts.

In this article, we’ll dive deep into clour recon, focusing on cutting-edge tactics that still work—even as companies get better at hiding their assets. Expect actionable steps you can implement right after you finish reading.


Why cloud recon?

Traditional cloud reconnaissance—like scanning for open S3 buckets—might feel played out. But guess what? Cloud footprints keep evolving, and so do the ways misconfigurations creep in. This means:

  • Ephemeral containers spin up and down, often with leftover vulnerabilities.
  • Microservices scatter essential services across multiple providers.
  • Serverless functions pop up in different regions, frequently misconfigured.

We need advanced strategies that hunt these ephemeral, hidden, or unusual assets. Let’s jump in! 🔍


1. 🕵️ Domain & DNS Snooping: Finding Hidden Cloud Endpoints

Why This Matters

In cloud environments, teams often set up DNS records that point to obscure services—like staging environments, serverless subdomains, or ephemeral test apps. If these records aren’t properly locked down, you can discover entire unprotected infrastructure clusters.

Action Steps

  1. Route53 Hunting: If you suspect AWS usage, check for ns-XXXX.awsdns-XX.org/.com/.co.uk.
  • Use tools like dnsx or subfinder with advanced DNS heuristics:
subfinder -d example.com -nW
dnsx -resp -r resolvers.txt

2. Focus on Non-Standard TLDs: Large orgs often create subdomains under unique TLDs for cloud tests (e.g., .cloud, .dev, .internal).

3. Check CNAME Records: A CNAME can reveal a domain that points to a serverless platform (like *.azurewebsites.net or *.cloudfront.net).

Pro Tip: If you find an unclaimed CNAME pointing to a cloud service, subdomain takeover can be immediate gold. 🏆


2. ☁️ Serverless & Function Sprawl: Mapping Ephemeral Cloud Functions

Why This Matters

Organizations spin up Lambda functions (AWS), Azure Functions, or Cloud Functions (GCP) for short-lived tasks—sometimes forgetting to remove them. These ephemeral endpoints can inadvertently remain accessible.

Action Steps

  1. Discover Function Patterns:
  • AWS Lambdas often appear in URLs like https://[functionName].lambda-url.[region].on.aws/.
  • Azure Functions might pop up at https://[functionName].azurewebsites.net/api/….

2. Fuzz Uncommon Endpoints: Tools like ffuf or wraith can brute force typical function naming:

ffuf -u "https://FUNCTIONNAME.azurewebsites.net/api/FUZZ" -w wordlist.txt -mc 200,403

3. Check for Environment Leaks: Many functions leak environment variables (like DB credentials) in verbose error logs or debug endpoints.

Pro Tip: Attack ephemeral endpoints fast—they might be gone tomorrow but can yield massive bounties if you catch them live. ⏱️


3. 🔄 Container Registries & Image Hunting

Why This Matters

Companies relying on microservices or ephemeral containers often push images to cloud registries (AWS ECR, Azure ACR, GCP Artifact Registry). If these registries aren’t set to private, you can pull images that store secrets, environment variables, or internal credentials. 🤯

Action Steps

  1. Registry Enumeration:
  • For AWS: look for ECR repositories (123456789012.dkr.ecr.[region].amazonaws.com).
  • For Azure: registry-name.azurecr.io references.
  • For GCP: gcr.io/PROJECT-ID/REPO.

2. Pull & Inspect: If you stumble upon an open registry:

docker pull 123456789012.dkr.ecr.us-east-1.amazonaws.com/insecure-app:latest
docker run --rm -it 123456789012.dkr.ecr.us-east-1.amazonaws.com/insecure-app:latest bash

Then scan for secrets in env files or code.

3. Check .dockerignore: Sometimes devs forget to exclude secrets from Docker images. 🪙

Pro Tip: Container logs or leftover config can hold goldmine credentials for internal services— leading to major bounties!


4. 🔒 “Ghost” Cloud Resources & Orphaned Services

Why This Matters

Large orgs spin up test environments in AWS/GCP/Azure, then forget them. These “ghost” resources might be fully accessible if they’re not behind WAF or IAM constraints.

Action Steps

  1. Inconsistent Naming Patterns: Staging services might use odd naming:
  • dev-[appName]-[region]
  • test-[serviceName].cloudfunctions.net

2. Check Org Repos: Searching public GitHub or GitLab for references to dev-, stage-, or temp- often yields domain or environment clues.

3. Automated “Orphan Hunt”: Create a custom script to:

  • Grab references from .tfstate or .yaml files if you find them online.
  • Check if those resources are still alive (e.g., using curl or AWS CLI to see if they exist).

Pro Tip: Orphaned services often skip fundamental security checks. 🏆


5. 🌐 Cross-Provider Linking & Multi-Cloud Mishaps

Why This Matters

Many companies run a “multi-cloud” approach: front-end in Azure, back-end on AWS, or logs in GCP. Sometimes, these bridging connections are left wide open.

Action Steps

  1. Trace DNS: If a front-end is in Azure, see if any DNS CNAME records point to AWS or GCP. This can reveal multi-cloud bridging.
  2. Check for Weak Federated Auth:
  3. Multi-cloud often relies on federated identity. If one environment uses shaky OIDC or JWT checks, you can pivot between them
  4. Correlate Bucket & Container Names: A project name might appear in both Azure Blob Storage and AWS S3. Searching for them can uncover more leaked assets.

Pro Tip: Exploiting “multi-cloud confusion” where tokens from one environment are accepted in another is a recurring theme—and can net huge bounties. 💰


6. 🤖 Using AI-Enhanced Recon Tools for Cloud Discovery

Why This Matters

Machine learning can speed up your scanning, finding patterns hidden in logs, file names, and sub-app references.

Action Steps

  • LLM-Assisted Wordlist Generation:
  • Feed a ChatGPT-like model the existing domain or project names.
  • Ask it to suggest likely ephemeral subdomain patterns, environment naming conventions, or Docker image tags.
  • AI-based Log Analysis: If you can access leaked logs, use an AI tool to quickly parse them for keywords like apikey, secret, or internal.app.
  • Automated Mutation: Let an LLM build permutations of likely cloud resource URIs.

Pro Tip: Devs often follow naming patterns that an LLM can infer—like serviceName-stage, serviceName-beta, etc. This can uncover entire hidden test environments. 🤩


7. ⚙️ Sample Attack Flow: Tying It All Together

  1. Start with DNS: Identify unusual subdomains or CNAME references leading to AWS, Azure, or GCP.
  2. Scrape JavaScript: Use regex to find *.cloudfunctions.net, *.amazonaws.com, or *.azurewebsites.net.
  3. Check Exposed Service: Attempt direct calls to discovered endpoints, verifying if authentication is enforced.
  4. Enumerate for Orphaned & Ephemeral Resources: Look for dev or test references in code, repos, or logs.
  5. Automate with AI**:** For further permutations or environment naming guesses.

When successful, you can gain unprecedented internal access—like reading sensitive data from a leftover S3 bucket or pivoting into a forgotten Azure Function. 🏆