· 6 min read
If you evaluated NodeZero (Horizon3.ai) or Pentera and walked away thinking "this is good, but I need it self hosted, open source, or I simply cannot send my network data to a vendor cloud", this is for you. Here is an honest look at the open source, self hostable options for autonomous security testing.
First, credit where it is due
NodeZero and Pentera are strong commercial platforms. They are mature and supported, and if your constraints allow a SaaS or appliance model with a vendor in the loop, they do the job well. The reasons teams look for an alternative are usually not "the product is bad", they are:
- Data residency and sovereignty. You cannot send internal IPs, hostnames, credentials or topology to a third party.
- Budget. Enterprise validation platforms are priced for enterprises.
- Self hosting and auditability. You want to run it on your own infrastructure and read the source.
- Extensibility. You want to modify the methodology, not file a feature request.
If none of those apply to you, a commercial platform is a fine choice. If one or more do, read on.
The open source options
- PentestGPT — an LLM assistant that guides a human through a pentest. Interactive, great for learning; you run the tools.
- Strix — Apache 2.0 autonomous agents focused on web application testing.
- PentAGI — an autonomous framework with an orchestrator and memory graph.
- CAI — a framework for building autonomous security testing agents.
- Darkmoon — GPL-3.0 platform closest in scope to the commercial validation tools: web, Active Directory, Kubernetes and API, with proof of exploitation on every finding. Full disclosure: this is our project.
The two things that actually decide it
If you are replacing NodeZero or Pentera specifically, two capabilities matter most, because they are where most open source tools stop short.
1. Beyond web: Active Directory and Kubernetes. Commercial validation platforms shine at internal network and AD attack paths. Most open source AI pentest tools are web only. That narrows the field fast, and it is the gap Darkmoon was built to cover.
2. Keeping data on your side while still using a strong model. This is the real sovereignty answer, and it is the reason people leave SaaS in the first place. Darkmoon runs on a local model if you want, and its privacy gateway goes further: the language model never sees real sensitive values at all. It works only on deterministic placeholders, real values are reinjected locally just before a tool runs, and exfiltration is blocked. We validated it end to end on OWASP Juice Shop with the gateway active the whole run: 56 vulnerabilities found while the model never saw a single real IP. The design is written up here.
How to decide in an afternoon
Clone the two or three that fit your constraints and run them against a lab you control:
- Web only, and you want a strong autonomous agent: try Strix or PentAGI.
- Leaving NodeZero or Pentera and you need AD plus Kubernetes plus data sovereignty: try Darkmoon.
- You want to study or teach the methodology: PentestGPT or hackingBuddyGPT.
All of these are free to clone and run, so the honest recommendation is to test on your own targets rather than trust any comparison, including this one. If open source and self hosted is a hard requirement for you, the field is finally good enough to take seriously.