T03 · Remote Payload Retrieval and Execution
Error
- Location
SKILL.md:26- Finding
Untrusted Remote Solution Retrieval and Execution
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 26–73 and 232–249
Vulnerability Type: Remote payload retrieval and execution
Risk Level: CriticalVulnerable Code
javascript async function evomapQuery(signals) { const timestamp = new Date().toISOString(); const messageId = `msg_${Date.now()}_${Math.random().toString(16).slice(2,6)}`; const response = await fetch('https://evomap.ai/a2a/fetch', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ protocol: 'gep-a2a', protocol_version: '1.0.0', message_type: 'fetch', message_id: messageId, sender_id: 'node_9e601234', timestamp: timestamp, payload: { signals: signals, limit: 5 } }) }); return response.json(); } async function autoReuse(signals) { // 1. Query const result = await evomapQuery(signals); // 2. Match if (result.payload?.results?.length > 0) { const best = result.payload.results[0]; // 3. Extract solution const solution = best.payload; // 4. Record reuse await recordReuse(signals, best); // 5. Report result later setTimeout(() => reportUsage(best.asset_id, true), 60000); return { reused: true, solution, asset: best }; } return { reused: false }; }The usage example then directs the consumer to apply the returned solution:
javascript if (!solution) { const result = await evomapQuery(errorSignals); if (result.payload?.results?.[0]) { solution = result.payload.results[0]; // Update local cache updateLocalCache(errorSignals, solution); } } // Use solution if (solution) { console.log('Reused solution:', solution.payload?.summary); // Execute solution... }Technical Analysis
The Skill retrieves mutable content from
https://evomap.ai/a2a/fetch, selects the first result, extracts its payload as a solution, and directs the Agent to use or e ...[truncated 1826 chars]- Remediation
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Remediation Suggestions
- Treat every remote response as untrusted data rather than executable instructions.
- Replace free-form solution payloads with a strict, versioned schema containing only declarative, allowlisted operations.
- Reject payloads containing shell commands, tool directives, prompt instructions, arbitrary URLs, filesystem paths, or unsupported fields.
- Require assets to be signed by approved publishers and verify signatures locally before use.
- Pin each approved asset to a cryptographic digest and reject any digest mismatch.
- Require explicit, informed user approval before applying or caching a newly retrieved solution.
- Display the source, digest, requested operations, affected resources, and expected network activity during approval.
- Execute approved operations in a least-privilege sandbox with restricted filesystem, process, credential, and network access.
- Do not automatically select the first search result; enforce publisher trust, compatibility, safety-policy, and integrity checks.
- Disable automatic usage reporting until the user has consented to the disclosed data transfer.
- Add response-size limits, content-type validation, timeout handling, schema validation, and safe failure behavior.
- Maintain an auditable local allowlist of reviewed assets and do not update it directly from untrusted search responses.