ssti-poc

ssti-poc is a skill for Claude Code, Codex from zebbern/termstack. It costs 4 tokens per session (2,953 once invoked), scanned A, original, no licence file.

A guide for finding server-side template injection (SSTI), a flaw where user input is inserted into a server template and can run code on the server.

In plain words
What is it for?
Use it to test template-driven applications for SSTI and possible remote code execution during authorized assessments.
Why use it?
It helps validate whether template input can be abused to execute commands remotely.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing. Also seen: agent in frontmatter.

Good fit Use it to test template-driven applications for SSTI and possible remote code execution during authorized assessments.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/zebbern/termstack/ssti-poc
Install

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.

Any agent
npx skills add zebbern/termstack --skill ssti-poc
Clone the repo
git clone --depth 1 https://github.com/zebbern/termstack

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for ssti-poc

README.md
[![agentmods](https://agentmods.dev/badge/skills/zebbern/termstack/ssti-poc/github.svg)](https://agentmods.dev/skills/zebbern/termstack/ssti-poc)
Your own site
<a href="https://agentmods.dev/skills/zebbern/termstack/ssti-poc"><img src="https://agentmods.dev/badge/skills/zebbern/termstack/ssti-poc/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.

agentmods 80×15 button for ssti-poc

Your own site · 80×15
<a href="https://agentmods.dev/skills/zebbern/termstack/ssti-poc"><img src="https://agentmods.dev/badge/skills/zebbern/termstack/ssti-poc.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 4 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,953 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00004 $0.02953
Opus 5.5 $0.00002 $0.01181
Sonnet 5.5 $0.00001 $0.00591
Haiku 4.5 $0.00000 $0.00295

Measured 1mo ago against content hash cfb6726040eb, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ssti-poc scanned grade A with 1 finding 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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

{{range.constructor("return global.process.mainModule.require('child_process').execSync('id')")()}}
.github/skills/ssti-poc/SKILL.md · 460 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

1 file 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.

Changes

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.

  1. 1mo ago First seen · 460 lines · 4 tokens per session scan A cfb6726040eb

Subscribe to this mod's changes

ssti-poc is a skill published in the GitHub repository zebbern/termstack (4 stars, last pushed 6mo ago), with no licence file. It adds 4 tokens to every session and 2,953 once invoked, about $0.0000 per session on Opus 5.5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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