competition-ad-certificate-abuse
About competition-ad-certificate-abuse
A downstream CTF skill for analyzing Active Directory certificate abuse after `$ctf-sandbox-orchestrator` establishes the sandbox and evidence priorities. It focuses on tracing certificate issuance through service acceptance to the resulting privilege.
Key features
- 01Map CA and certificate template policy
- 02Assess enrollment rights and certificate fields
- 03Trace certificate mapping to accepted services
- 04Reduce findings to a reproducible privilege chain
- 05Preserve certificate and acceptance evidence
Use cases
- 01Analyze a CTF path involving AD CS templates
- 02Determine how an issued certificate is accepted for privilege
- 03Document a minimal enrollment-to-privilege chain
Install
Copy the command and run it in a terminal.
npx skills add https:/ / github.com/ zhaoxuya520/ reverse-skill --skill competition-ad-certificate-abuseAfter installing, type/competition-ad-certificate-abusein Claude Code to confirm it loaded.
Bundled filesagents/openai.yamlreferences/ad-certificate-abuse.md
Details
From the project READMECompetition AD Certificate Abuse
Use this skill only as a downstream specialization after $ctf-sandbox-orchestrator is already active and has established sandbox assumptions, node ownership, and evidence priorities. If that has not happened yet, return to $ctf-sandbox-orchestrator first.
Use this skill when the decisive identity edge is certificate-based and the hard part is proving how a template or CA policy turns into accepted privilege.
Reply in Simplified Chinese unless the user explicitly requests English.
Quick Start
- Identify the CA, template, enrolling principal, and accepting service before diving into every certificate detail.
- Separate template enrollability from cert-based authentication or privilege acceptance.
- Record EKUs, subject or SAN controls, issuance requirements, enrollment rights, and mapping behavior in compact blocks.
- Tie the issued cert to one accepted path: PKINIT, Schannel, LDAPS, WinRM, or another mapped service.
- Reproduce the smallest certificate issuance-to-acceptance chain that yields the decisive privilege.
Workflow
1. Map CA And Template Trust
- Record CA configuration, template name, enrollment permissions, manager approval, authorized signatures, EKUs, subject requirements, and SAN behavior.
- Note whether the path depends on alternate subject names,
UPN, DNS names, enrollment agent behavior, or template supersedence. - Keep principal, template, and issuance policy tied together.
2. Prove Cert-To-Privilege Acceptance
- Show how the issued certificate is mapped or accepted: PKINIT, smartcard logon, Schannel auth, service mapping, or explicit certificate mapping.
- Record serial, subject, SAN, EKU, validity, and the exact service or domain edge that accepts it.
- Distinguish certificate issuance from the separate step where privilege is actually granted.
3. Reduce To The Decisive Abuse Chain
- Compress the path to the smallest sequence: enrollment right or misconfig -> issued cert -> accepted mapping -> resulting privilege.
- State clearly whether the weakness lives in template config, CA policy, mapping logic, relay path, or enrollment rights.
- If the task is really about delegation or ticket transformation after PKINIT, switch back to the tighter Kerberos skill.
Read This Reference
- Load
references/ad-certificate-abuse.mdfor the AD CS checklist, template checklist, and evidence packaging.
What To Preserve
- CA names, template names, rights, EKUs, issuance flags, SAN controls, and mapping details
- Issued certificate fields, serials, subjects, SANs, and the accepting service or logon path
- The smallest reproducible enrollment-to-privilege chain