web-app-penetration-testing

Original：🇺🇸 English

Translated

Pentest a web app or website end to end — black-box testing of a live URL, staging environment, or local dev server that finds and exploits real vulnerabilities (auth bypass, broken access control, IDOR, injection, XSS, SSRF, business logic) and proves each one with a working proof-of-concept instead of a signature match. Runs with Strix, either the self-hosted open-source CLI or the managed app.strix.ai cloud. Use when the user asks to pentest, hack, security-test, or audit their web app, website, web application, or staging site.

1installs

Sourceusestrix/strix

Added on2026-08-21

NPX Install

npx skill4agent add usestrix/strix web-app-penetration-testing

SKILL.md Content

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Pentest a web application

Black-box (and optionally source-assisted) penetration testing of a running web app with Strix's autonomous agents. Every reported finding is validated with a working exploit, so there are no signature-based false positives to triage.

Install, LLM setup, all CLI flags, and the managed-cloud alternative are covered in the penetration-testing-with-strix skill — read it if the target is not a running web app, or if

strix --version

fails. This skill is the web-app-specific workflow.

1. Confirm authorization and scope

Before running anything, establish:

The target is the user's (or they are explicitly authorized to test it). Never pentest a third-party site on a hunch.
Which environment. Prefer staging over production; agents send real exploit payloads and will create/modify data.
Out-of-scope paths — payment flows, mass-email endpoints, admin destructive actions, third-party SSO providers.
Credentials. Most real vulnerabilities live behind login. Without a test account, the agents only ever see the marketing surface.

Ask for anything missing rather than guessing.

2. Run the scan

bash

strix -n -t https://staging.example.com --max-budget 20 \
  --instruction "Test account: qa@example.com / <password>. In scope: /app/*, /api/*. Do not touch /billing or send email. Focus on access control between the two seeded orgs."

Notes that matter for web apps specifically:

Give it credentials via
--instruction
(or
```
--instruction-file
```
for anything long), including how to log in if the flow is unusual (magic link, SSO, MFA-exempt test user).
Two accounts beat one. Multi-tenant IDOR and broken-access-control bugs — consistently the highest-impact class in web apps — can only be proven when the agent can attempt cross-account access.
Add the repo for white-box depth when you have the source:
```
-t https://github.com/org/app -t https://staging.example.com
```
(or a local path). Source access materially improves coverage of business-logic and authorization flaws.
Localhost works. Point at
```
http://host.docker.internal:3000
```
(Docker Desktop) so the sandbox can reach a dev server on the host.
```
--scan-mode quick
```
for a fast dev-loop pass,
```
standard
```
(~30 min) for a normal review,
```
deep
```
for pre-release assurance. Always set
```
--max-budget
```
.

For a hosted run with no Docker/LLM key, or when the user wants a shareable dashboard and an auditor-ready PDF, use the cloud path in managed-pentesting-with-strix instead — same engine, same findings.

3. Review results

Read

strix_runs/<run>/penetration_test_report.md

first, then per-finding files in

vulnerabilities/

. Each contains the PoC — re-run it yourself to confirm before reporting to the user.

Exit codes:

no validated vulns in what was analyzed,

vulnerabilities found,

fatal error. A

is not proof of full coverage — if the budget or turn cap was hit the scan wraps up early, so check

run.json

status and cost against

--max-budget

before calling the app clean.

4. Fix and verify

Hand findings to the fix-security-vulnerabilities-with-strix skill: patch the root cause, then re-run Strix against the same target to prove the exploit no longer works. Re-testing is the only reliable confirmation a fix landed.

To keep the app tested on every change rather than once, wire Strix into CI with ci-security-scanning-with-strix.