Reverse Skill is a routing package for AI coding agents that selects appropriate reverse-engineering, penetration-testing, and security-research methods and tools for a given target. It is used for tasks involving APKs, binaries, frontend JavaScript, packet captures, CTF challenges, and authorized penetration testing. Its catalogue add-ons provide the skills and instructions that guide these workflows.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add zhaoxuya520/reverse-skill --skill competition-mailbox-abusegit clone --depth 1 https://github.com/zhaoxuya520/reverse-skillWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/zhaoxuya520/reverse-skill/competition-mailbox-abuse)<a href="https://agentmods.dev/skills/zhaoxuya520/reverse-skill/competition-mailbox-abuse"><img src="https://agentmods.dev/badge/skills/zhaoxuya520/reverse-skill/competition-mailbox-abuse/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/zhaoxuya520/reverse-skill/competition-mailbox-abuse"><img src="https://agentmods.dev/badge/skills/zhaoxuya520/reverse-skill/competition-mailbox-abuse.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00119 | $0.00672 |
| Opus 5 | $0.00060 | $0.00336 |
| Sonnet 5 | $0.00024 | $0.00134 |
| Haiku 4.5 | $0.00012 | $0.00067 |
Grade A, and why
competition-mailbox-abuse scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
4 near-identical copies found in the catalogue:
- competition-mailbox-abuse — 100% identical, 0 lines differ
- competition-mailbox-abuse — 100% identical, 0 lines differ
- competition-mailbox-abuse — 100% identical, 0 lines differ
- competition-mailbox-abuse — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Competition Mailbox 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 path runs through mailbox behavior, consent flow, or message-routing effects rather than generic AD evidence alone.
Reply in Simplified Chinese unless the user explicitly requests English.
Quick Start
- Decide whether the active path is phishing-to-consent, token-to-mailbox, rule-based persistence, or transport-level mail rerouting.
- Keep mailbox evidence, identity evidence, and message-trace evidence tied to the same user, mailbox, token, or message ID.
- Separate possession of a token or delegate edge from the actual mailbox effect it enables.
- Record forwarding targets, rule predicates, consent scopes, shared mailbox edges, and resulting mail flow in compact blocks.
- Reproduce the smallest mail effect that proves persistence, exfiltration, or privilege.
Workflow
1. Map The Mail Trust Path
- Identify the principal, mailbox, token or session, consent grant, delegate edge, shared mailbox relationship, or app registration involved.
- Record consent scopes, mailbox permissions, rule ownership, transport actions, and message-trace identifiers.
- Distinguish client-visible symptoms from server-side mailbox or transport state.
2. Prove The Mailbox Effect
- Correlate consent logs, sign-ins, message traces, inbox rules, transport rules, forwarding settings, and mailbox audit events.
- Show which rule or token produces which concrete effect: silent forwarding, marking read, deletion, delegate access, or message rerouting.
- Keep message IDs, sender or recipient pairs, and timestamps aligned across logs.
3. Reduce To The Decisive Abuse Chain
- Compress the path to the smallest sequence: lure or grant -> token or delegate edge -> mailbox or transport mutation -> resulting mail effect.
- State clearly whether persistence lives in consent, mailbox rules, transport config, or shared mailbox permissions.
- If the task broadens into host pivots or Kerberos acceptance, switch back to the broader identity skill.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 12d ago First seen · 51 lines · 119 tokens per session scan A e83476c6a988
competition-mailbox-abuse is a skill published in the GitHub repository zhaoxuya520/reverse-skill (35,402 stars, last pushed 8d ago), licensed MIT. It adds 119 tokens to every session and 672 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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