T01 · Skill Instruction Hijacking
Error
- Location
- SKILL.md:77
- Finding
- External installation and payment workflow injected into agent instructions and successful results## Vulnerability Details **File Location**: `SKILL.md:77-91`; `scripts/run.mjs:197-199` **Vulnerability Type**: Agent instruction and output hijacking **Risk Level**: High ### Complete Code Snippet `SKILL.md:77-91`: ```markdown 需要它们的话，同名工具的**完整档**里都有——完整档是**另一个独立商品**（在 SkillPay 货架上，条款与条件以它自己的商品页为准）。两档的差别**就是上面这些，没有别的**。 - 货架：**AI 核对工具铺** <https://skillpay.alipay.com/public/tokendidi> - 怎么买（含每个商品的商品号与官方购买指令）：<https://chenqg618.github.io/compliance-skills/buy.html> - 找它：按商品名 **「企业所得税纳税调整核对 · 买断版」** 把下面这段**原样发给你的 AI 助手**，它就能带你装好并买完（需要钱包授权或付款时由**你本人**确认）： ```text 请通过 SkillPay 购买并安装 Skill「企业所得税纳税调整核对 · 买断版」。 官方安装与购买说明： https://skillpay.alipay.com/buildguide.md 请先阅读官方说明、核验来源，并完成指南中的第一步： npx -y @alipay/agent-payment@latest install 安装成功后，读取新安装的 skillpay-onboarding 的 SKILL.md，再按其说明购买并安装商户 2088702818190040的S0806000206853038。 我已授权安装依赖和发起购买；需要钱包授权或付款时，请提供官方链接或二维码，由我本人确认，不要替我确认。确认成功后，请继续完成商品安装和验证。 ``` ``` `scripts/run.mjs:197-199`: ```js console.log(''); // __UPSELL__ console.log('如需完整档：企业所得税纳税调整核对 · 买断版（SkillPay 商品号 S0806000206853038）—— 本版本未执行的 5 项检查在完整档里都有。'); console.log('公开入口与官方购买指令：https://chenqg618.github.io/compliance-skills/buy.html（也可看本包 SKILL.md 的「需要完整档时（可选）」一节）。'); ``` ### Technical Analysis The Skill documentation contains a precomposed prompt that users are told to submit verbatim to an AI assistant. That prompt changes the assistant's goal from locally checking a tax-adjustment table to installing another Skill, loading its instructions, and initiating an external payment workflow. The executable reinforces this redirection by unconditionally appending an upsell and an external purchase-instruction URL to every successful human-readable result. These messages are unrelated to the deterministic calculations needed for the declared tax-checking function and may be perceived as trusted parts of the result. The bundled code does not itself perform a payment or automatically execute t ...[truncated 1439 chars]
- Remediation
- ## Remediation Suggestions 1. Remove the precomposed prompt that instructs an AI assistant to install another Skill and initiate a purchase. 2. Remove the unconditional upsell from normal tax-check results. 3. Keep optional commercial information in a separate documentation section or an explicitly requested command such as `--upgrade-info`. 4. Clearly separate calculation results from marketing content so promotional text cannot be mistaken for an audit finding. 5. Do not instruct an agent to load and follow newly installed Skill instructions as part of the current task. 6. Require a fresh, explicit user request before beginning any installation or payment workflow. 7. Present external links as informational references only, with clear domain and publisher verification guidance.