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Fix Security Vulnerabilities with Strix

Free

Efficiently remediate security issues found by Strix scans.

by usestrix50.8k stars on usestrix/strix
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Updated Aug 10, 2026
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Free · Opens the source repo

What Fix Security Vulnerabilities with Strix does

Fix Security Vulnerabilities with Strix is a Bash-based skill designed to help developers and security professionals effectively address security vulnerabilities identified by Strix, an open-source penetration testing tool. This skill streamlines the process of triaging, fixing, and verifying vulnerabilities by utilizing findings from Strix scans, whether they originate from the open-source CLI or the Strix cloud service. The skill is particularly useful for teams looking to enhance their application security posture by ensuring that vulnerabilities are not only patched but also verified to be resolved.

The skill begins by allowing users to gather findings from various sources, including detailed markdown files and JSON outputs from Strix scans. Each finding includes critical information such as severity, proof-of-concept (PoC) steps, and remediation guidance. Users can prioritize their work based on the severity of the vulnerabilities, ensuring that the most critical issues are addressed first. This triage process is essential for maintaining a secure application environment, especially in fast-paced development cycles.

Once vulnerabilities have been triaged, the skill guides users through the remediation process, emphasizing the importance of fixing the root cause rather than implementing superficial patches. It encourages best practices, such as leveraging built-in framework defenses and maintaining minimal diffs in code changes. After applying fixes, the skill facilitates verification by re-running Strix scans to ensure that the vulnerabilities have been effectively resolved, providing confidence in the security of the application.

This skill is ideal for developers, DevOps engineers, and security teams who need a structured approach to vulnerability management. By integrating the Fix Security Vulnerabilities with Strix skill into their workflows, teams can enhance their ability to respond to security findings efficiently and effectively, ultimately leading to more secure applications.

When to use it

Use this skill after conducting a Strix scan to remediate and verify security vulnerabilities in your application.

When not to use it

This skill is not suitable for addressing vulnerabilities outside the scope of Strix findings or for environments not utilizing Strix for scanning.

What you can build with it

Triage Vulnerabilities Post-Scan

After running a Strix scan, use this skill to triage and prioritize vulnerabilities for remediation.

Remediate Security Issues

Apply the skill to fix identified vulnerabilities by following best practices and leveraging existing code patterns.

Verify Fixes with Re-scanning

Use the skill to re-run Strix scans and ensure that all applied fixes have effectively resolved the identified vulnerabilities.

How to install Fix Security Vulnerabilities with Strix

View source

1. Install with the skills CLI

npx skills add usestrix/strix/fix-security-vulnerabilities-with-strix --agent claude-code

2. Or install it manually

Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.

Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs

Inside SKILL.md

Written by usestrix

Fix Strix findings and verify

Turn validated Strix findings into minimal, correct fixes — and prove they work by re-scanning.

1. Triage

Get the findings from wherever the scan ran:

  • OSS CLI — artifacts in strix_runs/<run-name>/:
    • vulnerabilities/*.md — one finding per file: description, severity, PoC steps or script, affected code locations, remediation guidance.
    • vulnerabilities.json — the same findings as JSON (ids, severity, CWE/CVE, code_locations with fix_before/fix_after suggestions when available).
  • Cloud (app.strix.ai) — fetch the scan's vulnerabilities[] via GET /api/v1/scans/{scanId} (or GET /api/v1/vulnerabilities org-wide). Each carries severity, cwe, endpoint, method, impact, technical_analysis, poc_description, poc_script_code and, for code findings, code_file/code_diff/code_before/code_after. See the managed-pentesting-with-strix skill for auth.

Order work by severity: critical → high → medium → low. Every Strix finding was validated with a working proof-of-concept, so do not dismiss findings as false positives without re-testing the PoC yourself.

2. Fix

For each finding:

  1. Reproduce it with the PoC from the finding file when feasible.
  2. Fix the root cause, not the specific payload (e.g. parameterize all queries, don't blocklist one string; enforce authorization in the handler, don't hide the endpoint).
  3. Prefer the framework's built-in defense (ORM parameterization, template auto-escaping, CSRF middleware, centralized authz) over ad-hoc sanitization.
  4. Keep the diff minimal and apply the repo's existing patterns. Finding files often include fix_before/fix_after snippets — use them as a starting point, not verbatim.

Common finding classes and expected fixes: injection → parameterization/escaping at the sink; IDOR/broken access control → object-level authorization checks; SSRF → allowlist + block internal ranges; XSS → context-aware output encoding + CSP; secrets exposure → rotate the secret AND remove it from code/history; auth issues → fix the server-side check (never client-side).

3. Verify by re-running Strix

After fixing, re-scan scoped to the fixed area and confirm the finding is gone. Verify in whichever environment you scanned (or both):

OSS CLI:

# Re-test just the changed files (fast). Resolve the repo's real default
# branch instead of assuming origin/main (many repos use master/develop).
# Avoid the current branch's own upstream as the base — its merge base with
# HEAD would be HEAD, giving an empty diff and a falsely clean result.
DIFF_BASE=$(git symbolic-ref --quiet --short refs/remotes/origin/HEAD 2>/dev/null)
# origin/HEAD can be a dangling symbolic ref — keep it only if its target exists.
git rev-parse --verify --quiet "$DIFF_BASE" >/dev/null 2>&1 || DIFF_BASE=""
if [ -z "$DIFF_BASE" ]; then
  for b in origin/main origin/master origin/develop; do
    git rev-parse --verify --quiet "$b" >/dev/null && DIFF_BASE="$b" && break
  done
fi
# No silent fallback: a guess like HEAD~1 would cover only the last commit of a
# multi-commit fix branch. If no base resolves, ask the user for the base branch
# (or use the focused --instruction verification below, which needs no diff base).
[ -n "$DIFF_BASE" ] || { echo "Set DIFF_BASE to the branch your fix will merge into." >&2; exit 1; }
strix -n -t ./ --scan-mode quick --scope-mode diff --diff-base "$DIFF_BASE" --max-budget 5

# Or re-test with the original finding as focus (no diff base needed)
strix -n -t ./ --instruction "Verify the SQL injection in app/api/search.py is fixed. Original PoC: <poc>" --max-budget 5

Exit codes: 2 = findings remain (read the new strix_runs/<run>/vulnerabilities/ and iterate); 0 = clean for what was analyzed. Before trusting a 0, confirm the run wasn't cut short — check run.json for a completed status and compare its llm_usage.cost with --max-budget: a hard budget stop leaves status: "stopped", but a run that wrapped up on a budget warning records "completed" with partial coverage. Give verification enough budget to finish, and prefer re-running the specific PoC as the ground-truth signal.

Cloud: rerun with the same config and re-poll, then confirm the finding no longer appears:

new_id=$(curl -sS "$BASE/scans/$scan_id/rerun" "${auth[@]}" -X POST | jq -r .scan_id)
# poll GET /scans/$new_id until completed, then check its vulnerabilities[]

Or, if the cloud scan came from a repo/PR, trigger a fresh PR review on the fix branch (POST /pr-reviews/start). The platform also retests a single finding directly: POST /api/v1/vulnerabilities/{vulnerabilityId}/retest.

  • Also re-run the PoC manually when it is a simple request/script — fastest signal.
  • Run the project's own test suite to make sure the fix doesn't break behavior.

4. Report

Summarize per finding: severity, root cause, fix applied (file:line), verification result (re-scan clean / PoC no longer reproduces). Never include live secrets in the report; if a secret leaked, state that rotation is required.

Frequently asked questions about Fix Security Vulnerabilities with Strix

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