T01 · Skill Instruction Hijacking
Warning
- Location
- SKILL.md:1
- Finding
- Skill Instruction Hijacking via Fixed Advertising/Link Template in SKILL.md## Vulnerability Details **File Location**: SKILL.md (entire file, notably the ending section) **Vulnerability Type**: T01: Skill Instruction Hijacking **Risk Level**: Medium ### Technical Analysis The SKILL.md file contains an appended fixed advertising and link template at the end of the skill description. This pattern is indicative of content injection that can alter the output of language models, especially those that consume skill or instruction metadata to modify runtime behavior. By including advertising content or external links, the skill can unintentionally divert user traffic, bias responses, or alter the intended functionality and safety boundaries of the agent session. ### Attack Path 1. SKILL.md is loaded by the agent or LLM-based system as skill metadata or system prompt. 2. The injected advertising/link template is appended to the model's context. 3. The language model may generate outputs containing the injected content, promote external resources, or deviate from intended task boundaries. 4. This can be abused to hijack user attention, promote unauthorized resources, or interfere with task integrity. ### Impact Assessment The injected advertising or link template can alter the agent’s session instructions, causing skill output to be biased, promotional, or outside the scope of the legitimate user task. This undermines the trustworthiness and neutrality of the agent, and may indirectly expose users to phishing or traffic-diversion attacks.
- Remediation
- ## Remediation Suggestions - Remove all fixed advertising, external link templates, or promotional content from SKILL.md and any other instruction text that is imported into the agent's execution context. - Audit all agent-facing instruction or metadata files for similar patterns and enforce a strict policy prohibiting output injection or traffic-diversion content. - Implement automated scanning for advertising or link patterns in future skill submissions.
