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 UnboundCompute/security-agent-skills --skill mapping-service-account-impersonation-chainsgit clone --depth 1 https://github.com/UnboundCompute/security-agent-skillsWrote 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/unboundcompute/security-agent-skills/mapping-service-account-impersonation-chains)<a href="https://agentmods.dev/skills/unboundcompute/security-agent-skills/mapping-service-account-impersonation-chains"><img src="https://agentmods.dev/badge/skills/unboundcompute/security-agent-skills/mapping-service-account-impersonation-chains/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/unboundcompute/security-agent-skills/mapping-service-account-impersonation-chains"><img src="https://agentmods.dev/badge/skills/unboundcompute/security-agent-skills/mapping-service-account-impersonation-chains.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00170 | $0.01888 |
| Opus 5.5 | $0.00068 | $0.00755 |
| Sonnet 5.5 | $0.00034 | $0.00378 |
| Haiku 4.5 | $0.00017 | $0.00189 |
Grade A, and why
mapping-service-account-impersonation-chains 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 133 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Mapping service-account impersonation chains: when one identity can become another
Cloud identity models let a principal act as a service account through impersonation or short-lived-token generation, and each such grant is an edge in a graph: whoever holds it can become the target identity and inherit its permissions. Individually these grants look benign, a deployment principal impersonating a deploy account, an automation user minting a token for a job account. The risk is transitive. If the target account can itself impersonate a third, and that a fourth, a low-privileged starting principal can walk the chain into an administrative identity no single grant intended. You find these by treating impersonation and token-creator grants as edges and mapping where a starting principal can reach.
When to use
- Principals can impersonate service accounts or generate short-lived tokens for them.
- An actAs, token-creator, or equivalent grant lets one identity act as another.
- You need to know the transitive reach of a starting principal through chained impersonation.
Scope check
Test impersonation only in projects and organizations you own or are authorized to assess. A confirming impersonation obtains credentials for the target identity, so stay inside the authorized projects and never impersonate an account outside the engagement. If you can't name the authorization, stop.
The loop
-
Establish the starting principal and its intended reach first. Name the principal you are analyzing from, a user, a workload identity, a CI principal, and what identities it is legitimately supposed to act as. This is the false-positive killer: an impersonation grant that lets a principal act only as the one account its job requires is correct even in a large project. Name the intended reach, then map the actual reach against it.
-
Enumerate the impersonation and token-creator edges. Inventory every grant that lets one identity act as another: impersonation roles, token-creator or actAs permissions, and any binding that produces credentials for a service account. Each is a directed edge from the grantee to the target account. Record the edges, not just the roles, because the graph is what matters.
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.
- 1mo ago First seen · 133 lines · 170 tokens per session scan A afd95447d2e0
mapping-service-account-impersonation-chains is a skill published in the GitHub repository UnboundCompute/security-agent-skills (5 stars, last pushed 1mo ago), licensed MIT. It adds 170 tokens to every session and 1,888 once invoked, about $0.0007 per session on Opus 5.5. 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 2026-09-05.
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