🔒 Fix SSRF DNS Rebinding Vulnerability#13
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Introduced a custom `undici` Agent with a secure lookup function that validates IP addresses against internal ranges immediately before connection. This prevents Time-of-Check Time-of-Use (TOCTOU) attacks where DNS rebinding could bypass initial validation. - Added `IPGuard.secureLookup` and `IPGuard.getSecureDispatcher`. - Updated `Fetcher` to use the secure dispatcher when no proxy is configured. - Added unit tests for `IPGuard` and updated `Fetcher` integration tests.
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Explicitly typed the callback arguments in `dns.lookup` to prevent TypeScript from inferring `never` for the `address` parameter when handling array results, which caused a build failure.
Updated integration tests (`crawler.test.ts`, `fetcher.test.ts`) to mock `IPGuard.getSecureDispatcher` so that it returns the `MockAgent` configured in the tests, ensuring the tests can intercept requests. Updated `redirect_safety.test.ts` to mock `undici.Agent` which was missing from the existing mock and causing instantiation errors.
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This PR fixes a critical SSRF vulnerability caused by a DNS Rebinding race condition. Previously, the
Fetchervalidated hostnames usingIPGuard.validateHostbefore making a request, but the subsequent request performed a new DNS resolution, allowing an attacker to switch the IP to an internal address between the check and the use.The fix introduces a custom
undiciAgent that hooks into the DNS lookup phase. By validating the resolved IP address immediately before the connection is established, we eliminate the race condition window.Changes:
plugins/core/src/core/security/ipGuard.ts: AddedsecureLookupmethod andgetSecureDispatcherhelper.plugins/core/src/crawler/fetcher.ts: UpdatedFetcherto usesecureDispatcherfor direct connections.plugins/core/tests/ipGuard.test.ts: Added tests for the new secure lookup logic.plugins/core/tests/fetcher_safety.test.ts: Updated mocks to supportundici.Agent.Risk:
Without this fix, an attacker could control a DNS server to return a public IP during validation and a private/internal IP during the request, allowing them to access internal network resources via the crawler.
Verification:
secureLookup.PR created automatically by Jules for task 7903518880006150675 started by @saurabhsharma2u