PentestGPT

// Overview

PentestGPT is an open-source agent that uses large language models to perform penetration testing and capture-the-flag (CTF) challenges. It was published at USENIX Security 2024 and has since grown into an agentic tool that can work through a target on its own.

The current v1.0 release runs an autonomous iteration loop: the agent works continuously, keeps a context file with its progress, and restarts with that prior context when it hits a limit. The loop stops when a flag is captured or the maximum number of iterations is reached.

PentestGPT also keeps the classic human-in-the-loop experience from the original paper as a modernized legacy mode. That mode uses three cooperating LLM sessions for reasoning, generation, and parsing, and lets you drive the session interactively while it maintains a Pentesting Task Tree.

// What it does

• Autonomous agent pipeline that runs penetration tests and CTFs with little or no human input
• Iteration loop with a saved context file, so the agent can restart with prior progress and stop on flag capture or a max-iteration limit
• Live walkthrough and real-time feedback that show each step as the agent works through a challenge
• Multi-category coverage for web, crypto, reversing, forensics, PWN, and privilege escalation tasks
• Interactive multi-LLM legacy mode supporting OpenAI, Anthropic, Google Gemini, DeepSeek, xAI Grok, Qwen, Moonshot Kimi, and local Ollama models
• Session persistence to save and resume penetration testing runs

// Getting started

PentestGPT needs Python 3.12+, the uv package manager, and an installed and authenticated Claude Code CLI for the autonomous agent. Clone the repository, install dependencies, then run the agent against a target.

git clone https://github.com/GreyDGL/PentestGPT.git
cd PentestGPT
make install

pentestgpt --target 10.10.11.234

pentestgpt --target 10.10.11.50 --instruction "WordPress site, focus on plugin vulnerabilities"

pentestgpt --target 10.10.11.234 --max-iterations 5

pentestgpt-legacy

pentestgpt-legacy --reasoning-model claude-opus-4-8 --parsing-model gemini-3.5-flash

pentestgpt-legacy --list-models

Commands and code are distilled from the project's own documentation — always check the official repo for the latest.

// When to use it

• Running autonomous penetration tests against an authorized target to find and exploit vulnerabilities
• Solving capture-the-flag challenges across categories such as web, crypto, reversing, forensics, PWN, and privilege escalation
• Driving a human-in-the-loop pentesting session that maintains a task tree and suggests next steps interactively
• Comparing how different LLM providers and models perform on security reasoning tasks via the legacy mode's model registry and smoke test

// How PentestGPT compares

PentestGPT alongside other open-source security agents tools AI/TLDR tracks, ranked by GitHub stars.