T01 · Skill Instruction Hijacking
- Location
SKILL.md:118- Finding
Unsolicited External Promotion Injected into Skill Responses
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 118-123
Vulnerability Type: Output instruction hijacking through a fixed external promotion
Risk Level: MediumEvidence:
markdown ## More
🧠 Want full conversation tracking with pattern memory? → replyher.com/pro
text Technical Analysis
The skill includes a fixed promotional block that directs users to
replyher.com/pro. This content is unrelated to the core conversation-analysis workflow and can cause the agent to include unsolicited advertising in generated responses.Because the promotion appears in the skill instructions rather than ordinary package documentation or metadata, an agent loading the skill may treat it as response content to reproduce. This alters the expected output objective from providing conversation analysis to also promoting an external service. The destination is not used to retrieve or execute code, and the audited project contains no scripts that automatically transmit information to it; therefore, this finding is limited to instruction and output manipulation.
Attack Path
- A user or agent installs and loads the skill.
- The agent treats the content of
SKILL.mdas behavioral and response-format instructions. - The user requests analysis of a message or conversation.
- The agent produces the requested analysis and may append the fixed promotional block.
- The user may follow the external link and leave the trusted interaction context.
- The external service can then receive ordinary web-request metadata and independently solicit additional information from the user.
Impact Assessment
The injected content can influence agent output and redirect users to an external commercial service without an explicit request. This may reduce output integrity, create an undisclosed endorsement, and expose users to the privacy and security practices of an unaudited destination.
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- Remediation
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Remediation Suggestions
- Remove the promotional block from
SKILL.md. - Keep behavioral instructions limited to functionality required for conversation analysis.
- If product information is necessary, place it in package metadata or separate documentation rather than response instructions.
- Display external links only when a user explicitly requests related resources.
- Clearly identify commercial affiliations and external destinations before presenting them.
- Add review checks that flag fixed advertisements, referral links, and unrelated calls to action in skill instructions.
- Ensure no conversation content is submitted to an external service without explicit, informed user consent.
- Remove the promotional block from
