Base
Hardened build
minimal ports, security patches applied at build time
Subfinder on Ubuntu 24.04
Azure
Security
Subfinder, a fast passive subdomain discovery tool that maps a domain's attack surface by reading public sources without ever touching the target.
Overview
Subfinder is an open source passive subdomain enumeration tool used to discover the valid subdomains of a domain quickly and quietly. Instead of probing the target, it queries dozens of public passive sources, certificate transparency logs, passive DNS aggregators and web archives, then merges and de duplicates the results into a clean list of subdomains. Because it is strictly passive it sends no traffic to the domain being mapped, so it is safe and non intrusive to run against any target you are authorised to assess.
It suits security teams and penetration testers mapping the external attack surface of the domains they own or are engaged to test, and it fits neatly into automated recon and continuous attack surface monitoring pipelines where its machine readable output feeds the next tool.
Why the cloudimg image
Subfinder is a command line tool with no web interface, no listening service and no login of its own, so what matters is that the image is assembled cleanly and stays that way, and cloudimg ships it exactly so. The only open port is SSH with the key you choose at launch, and no credential is baked into the image. cloudimg turns the bare binary into a working appliance: optional passive source API keys are read from one system configuration file so they apply in every context including scheduled jobs and automation, a daily enumeration timer can continuously map the domains you list and writes machine readable reports for the next tool to pick up, and a self test is included so you can prove the scanner really enumerates on your own instance. The base is fully patched with unattended security upgrades enabled, and every deployment comes with a paired deploy guide and 24/7 cloudimg support.
Common uses
- Map the external attack surface of domains you own or are engaged to test
- Feed discovered subdomains into automated recon and scanning pipelines
- Continuously monitor a domain's subdomains on a schedule
More in Security
KeePass Password Manager
Security
KeePass is a free, open source password manager that stores all your passwords in a highly encrypted database. The datab...
CrowdSec
Security
This image runs CrowdSec, the free and open source collaborative behavioural security engine.
Ollama GPU-Accelerated LLM Server
Security
This image runs Ollama 0.30, the easiest way to run open large language models locally - pull and serve Llama, Mistral, ...
OWASP ZAP
Security
This image runs OWASP ZAP (the Zed Attack Proxy), the world's most widely used open source web-application security scan...
step-ca
Security
This image runs step-ca, the open source online certificate authority from Smallstep for secure, automated X.509 and ACM...
Trivy Security Scanner
Security
This image runs Trivy, the open source, Apache-2.0 licensed all-in-one security scanner from Aqua Security.