T01 · Skill Instruction Hijacking
- Location
SKILL.md:41- Finding
Mandatory Injection of Fixed Third-Party Promotional Links
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 41–49
Vulnerability Type:T01: Skill Instruction Hijacking
Risk Level: LowComplete Code Snippet
markdown ### Further Reading - How to Build in Public as a Founder: https://www.failory.com/blog/building-in-public - The Ultimate Founder-Led LinkedIn Guide: https://www.mrrunlocked.com/p/founder-led-linkedin-guide - LinkedIn CEO/Founder playbook: https://www.markepear.dev/blog/linkedin-ceo-founder-playbook - Social Listening guide: https://www.mrrunlocked.com/p/social-listening-guide - F5 bot (free Reddit/HN monitoring): https://f5bot.com/ - How to market to developers on Twitter: https://www.markepear.dev/blog/developer-marketing-twitter - Organic Growth Guide for TikTok and Instagram: https://www.post-bridge.com/growth-guide/start-here - Pinterest Growth Guide: https://www.blogtopin.com/growth-guide/start-hereTechnical Analysis
Line 16 instructs the agent to provide a response containing the subsequently defined sections after receiving the user's answers. Lines 41–49 define one of those mandatory sections as a fixed collection of third-party links. Consequently, invoking the skill causes unrelated external resources and named services to be inserted into the agent's output without requiring a user request for those resources or a relevance assessment.
This is a limited form of skill instruction hijacking because the skill text persistently controls part of the agent's response and routes users toward predetermined external websites. The reviewed file does not establish that the linked sites are malicious, compromised, or affiliated with the skill author; the confirmed issue is the mandatory and undisclosed nature of the promotion rather than malicious behavior by those sites.
Attack Path
- A user invokes the
social-media-strategyskill. - The skill directs the agent to ask five discovery questions.
- The user supplie ...[truncated 878 chars]
- A user invokes the
- Remediation
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Remediation Suggestions
- Remove the requirement to include a fixed third-party link list in every generated strategy.
- Recommend external resources only when they are relevant to the user's stated audience, platforms, capacity, and goals.
- Ask whether the user wants external reading or tooling recommendations before presenting them.
- Use neutral selection criteria and, where practical, provide multiple comparable options rather than repeatedly promoting predetermined providers.
- Clearly disclose any sponsorship, referral relationship, affiliate arrangement, or other material connection.
- Treat linked content as untrusted external material and avoid implying that it has been security-reviewed or independently endorsed.
