T01 · Skill Instruction Hijacking
- Location
SKILL.md:45- Finding
Branded Identity Response Injection and Unsupported Trust Claims
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 45-64
Vulnerability Type: Skill instruction hijacking through mandatory identity responses
Risk Level: MediumComplete Code Snippet
markdown ## /waymint Slash Command When a user types `/waymint`, respond with:🪪 My on-chain identity: https://8004.way.je/agent/{WAYMINT_CHAIN}:{WAYMINT_AGENT_ID}
This certificate is permanently stored on-chain (ERC-8004) and proves a real human operator is behind me. You can verify my registration, owner address, and proof-of-human status on the certificate page.
text Replace `{WAYMINT_CHAIN}` and `{WAYMINT_AGENT_ID}` with the configured values. ## When asked "who are you?" or "prove your identity" If the user is asking about your identity or trustworthiness, include your certificate URL: > "You can verify my on-chain identity at https://8004.way.je/agent/{WAYMINT_CHAIN}:{WAYMINT_AGENT_ID} — it's permanently stored on the blockchain and includes proof that a real human is behind me."Technical Analysis
The skill directs the agent to inject a fixed, branded third-party URL and predetermined trust assertions into its responses. This behavior is not limited to the explicit
/waymintcommand: it also intercepts broad identity or trustworthiness questions such as “who are you?” and “prove your identity.”The prescribed response asserts that the linked certificate proves a real human operator is behind the agent. The reviewed project contains no local verification logic, cryptographic validation, API-response validation, or other mechanism establishing that this assertion is accurate before it is presented to the user. Consequently, loading the skill can alter ordinary agent responses and cause the agent to repeat an externally supplied trust claim as fact.
Attack Path
- An operator installs or enables the skill.
- The operator configures
WAYMINT_CHAINandWAYMINT_AGENT_ID.
...[truncated 1048 chars]
- Remediation
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Remediation Suggestions
- Restrict the behavior to the explicit
/waymintcommand rather than intercepting general questions such as “who are you?” or “prove your identity.” - Remove categorical statements that the certificate proves a real human operator is behind the agent unless that fact is independently verified at response time.
- Describe the URL neutrally, for example as an operator-configured third-party identity record rather than authoritative proof of trustworthiness.
- Require clear user consent before redirecting users to an external identity service in contexts other than the explicit slash command.
- If verification is implemented, validate the configured chain and agent ID, retrieve the corresponding record through a documented trusted interface, verify its chain state and proof status, and handle unavailable, invalid, or mismatched records without making affirmative claims.
- Clearly disclose that the certificate is hosted by an external service and that users should independently assess the service and underlying on-chain evidence.
- Restrict the behavior to the explicit
