fix(services): reject non-routable ENR targets in DAS Guardian scan - #817
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damilolaedwards wants to merge 1 commit into
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fix(services): reject non-routable ENR targets in DAS Guardian scan#817damilolaedwards wants to merge 1 commit into
damilolaedwards wants to merge 1 commit into
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POST /api/v1/das-guardian/scan takes an arbitrary ENR from any unauthenticated caller (enabled by default, no auth required) and had dora's server dial whatever IP:port the ENR encoded, via eth-das-guardian's ConnectNode -> host.Connect. Neither the handler, services.DasGuardian, nor the library itself filtered the target - confirmed by driving the actual library dial code end-to-end against a local victim listener and observing the connection arrive. This let an anonymous caller use dora's server as an outbound proxy: internal network reconnaissance (loopback/RFC1918 targets), or cloud metadata endpoints (169.254.169.254) on AWS/GCP/Azure deployments. Fix: validate the parsed ENR's IP in both services.DasGuardian.ScanNode and ScanNodeWithCallback (the two entry points a request can take, covering the plain and random-slot-selection modes) before it ever reaches the dial path. Rejects loopback, RFC1918/ULA private ranges, link-local (which covers the cloud metadata range), unspecified, and multicast addresses using net.IP's standard classifiers. Tests: a table test covering every rejected class plus an ordinary public address that must still pass, and an end-to-end test that drives the real fixed ScanNode against a loopback target and asserts no connection ever reaches a victim listener - the same scenario the original PoC used to prove the bug. Confirmed the end-to-end test fails to build without validateScanTarget (the protection doesn't exist), then restored the fix. go build, go vet, gofmt, and the full services test suite (including -race) are clean.
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Summary
POST /api/v1/das-guardian/scantakes an arbitrary ENR from any unauthenticated caller (enabled by default, no auth required) and had dora's server dial whatever IP:port the ENR encoded, viaeth-das-guardian'sConnectNode->host.Connect. Neither the handler,services.DasGuardian, nor the library itself filtered the target, confirmed by driving the actual library dial code end-to-end against a local victim listener and observing the connection arrive.This let an anonymous caller use dora's server as an outbound proxy: internal network reconnaissance (loopback/RFC1918 targets), or cloud metadata endpoints (
169.254.169.254) on AWS/GCP/Azure deployments.Fix
Validate the parsed ENR's IP in both
services.DasGuardian.ScanNodeandScanNodeWithCallback(the two entry points a request can take, covering the plain and random-slot-selection modes) before it ever reaches the dial path. Rejects loopback, RFC1918/ULA private ranges, link-local (which covers the cloud metadata range), unspecified, and multicast addresses usingnet.IP's standard classifiers.Tests
ScanNodeagainst a loopback target and asserts no connection ever reaches a victim listener, the same scenario used to prove the bug in the first place.Confirmed the end-to-end test fails to build without
validateScanTarget(the protection doesn't exist), then restored the fix.go build,go vet,gofmt, and the fullservicestest suite (including-race) are clean.