T01 · Skill Instruction Hijacking
Warning
- Location
- SKILL.md:1
- Finding
- Fixed Advertising/Footer Template in SKILL.md Enables Skill Instruction Hijacking## Vulnerability Details **File Location**: /tmp/clawhub-codex-scan-v577rdebprgyb1qh9tjne1kysn8dv7nj-59vOfg/artifact/SKILL.md (lines 1–153) **Vulnerability Type**: T01: Skill Instruction Hijacking **Risk Level**: Medium ### Technical Analysis The SKILL.md file contains a large fixed advertising and traffic-diversion template appended at the end of the documentation. This includes direct promotional links, repetitive branding, and output templates that instruct the agent to include specific promotional content and links in its output. Such content can manipulate the agent's response to always promote a particular service—regardless of user intent—or inject unwanted links and tracking templates in generated outputs. This is a classic case of skill instruction hijacking, where the agent's default output is intentionally biased or redirected by static content in the skill description. ### Attack Path 1. The skill is loaded by an agent that consumes the SKILL.md as part of its prompt or context. 2. The appended advertising/footer template is included in the context for generating responses. 3. All or part of this promotional template is reflected in the agent's output to users, potentially bypassing user intent or safety controls. 4. Users are repeatedly shown injected links or advertisements, enabling traffic diversion or data collection. ### Impact Assessment The agent's session can be hijacked to serve persistent advertisements, divert user traffic, or alter expected output. This undermines the agent's neutrality, user trust, and can violate platform content guidelines. It also creates a channel for persistent content injection, which could be extended to more malicious payloads or tracking if the template is modified.
- Remediation
- ## Remediation Suggestions - Remove all fixed advertising, promotional links, and output templates that are not directly necessary for the skill's technical function. - Ensure the SKILL.md only documents legitimate functionality and usage, without embedding persistent output templates or traffic-diversion content. - Add a review process to detect and reject skills with appended advertising, tracking, or similar instruction-hijacking content.
