T09 · Insecure Skill Coding Practices
Error
- Location
index.js:85- Finding
Forgeable Proof-of-Interaction Verification
- Content
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138) { const extraData = "0x" + tx.data.slice(138); if (extraData.length === 66) { verifiedCount++; } } ``` ```javascript // Strict check on Proof TX to prevent gas waste let appendData = ""; if (proofTx) { if (!ethers.isHexString(proofTx) || proofTx.length !== 66) { return "❌ Invalid Proof Transaction. Must be a 32-byte hash (0x + 64 chars)."; } appendData = proofTx.replace("0x", ""); console.log(`🔗 Attaching Proof: ${proofTx}`); } ``` The unvalidated value is subsequently appended directly to the rating transaction: ```javascript // Encode Function + Append Stashed Data let data = contract.interface.encodeFunctionData("logReputation", [agentId, score]); data = data + appendData; ``` ### Technical Analysis The implementation treats any 32-byte calldata suffix as a verified Proof of Interaction. Validation in `rate_agent` establishes only that `proofTx` is a correctly formatted hexadecimal value of the expected length. During auditing, the code similarly checks only that the appended data is 32 bytes long. The skill does not retrieve the referenced transaction or verify that: - The transaction hash corresponds to an existing transaction. - The referenced transaction completed successfully. - The reviewer was a participant in that transaction. - The rated agent or an identity associated with that agent was involved. - The transaction represents an interaction relevant to the reputation review. - The suffix was produced through the skill rather than manually crafted calldata. Consequently, an arbitrary 32-byte value, including a randomly generated value or an unrelated ...[truncated 1705 chars]- Remediation
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