expression-language-injection

expression-language-injection is a skill for Claude Code, Codex from Prohao42/aimy-skill. It costs 45 tokens per session (2,327 once invoked), scanned A, original, no licence file.

A security testing guide for expression-language injection, where attacker-controlled text is evaluated as code by Java expression systems such as SpEL or OGNL.

In plain words
What is it for?
It is for testing Java applications and frameworks such as Spring, Struts2, and Confluence when they process these expressions.
Why use it?
It helps find places where user input could be evaluated instead of treated as ordinary text, potentially exposing application actions or data.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/prohao42/aimy-skill/expression-language-injection
Any agent
npx skills add Prohao42/aimy-skill --skill expression-language-injection
Clone the repo
git clone --depth 1 https://github.com/Prohao42/aimy-skill

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 expression-language-injection

README.md
[![agentmods](https://agentmods.dev/badge/skills/prohao42/aimy-skill/expression-language-injection.svg)](https://agentmods.dev/skills/prohao42/aimy-skill/expression-language-injection)
Your own site
<a href="https://agentmods.dev/skills/prohao42/aimy-skill/expression-language-injection"><img src="https://agentmods.dev/badge/skills/prohao42/aimy-skill/expression-language-injection.svg" alt="Measured on agentmods" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,327 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00045 $0.02327
Opus 5 $0.00023 $0.01163
Sonnet 5 $0.00009 $0.00465
Haiku 4.5 $0.00005 $0.00233

Measured 5d ago against content hash dd96ba349b08, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

expression-language-injection 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 5d 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.

ai-mian/hack-skills/skills/expression-language-injection/SKILL.md · 244 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

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. 5d ago First seen · 244 lines · 45 tokens per session scan A dd96ba349b08

Subscribe to this mod's changes

expression-language-injection is a skill published in the GitHub repository Prohao42/aimy-skill (135 stars, last pushed 11d ago), with no licence file. It adds 45 tokens to every session and 2,327 once invoked, about $0.0002 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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