SpiceDB binding metrics port to untrusted networks and can leak command-line flags

Background

The spicedb serve command contains a flag named --grpc-preshared-key which is used to protect the gRPC API from being accessed by unauthorized requests. The values of this flag are to be considered sensitive, secret data.

The /debug/pprof/cmdline endpoint served by the metrics service (defaulting running on port 9090) reveals the command-line flags provided for debugging purposes. If a password is set via the --grpc-preshared-key then the key is revealed by this endpoint along with any other flags provided to the SpiceDB binary.

Impact

All deployments abiding by the recommended best practices for production usage are NOT affected:

• Authzed’s SpiceDB Serverless
• Authzed’s SpiceDB Dedicated
• SpiceDB Operator

Users configuring SpiceDB via environment variables are NOT affected.

Users MAY be affected if they expose their metrics port to an untrusted network and are configuring --grpc-preshared-key via command-line flag.

Workarounds

To workaround this issue you can do one of the following:

• Configure the preshared key via an environment variable (e.g. SPICEDB_GRPC_PRESHARED_KEY=yoursecret spicedb serve)
• Reconfigure the --metrics-addr flag to bind to a trusted network (e.g. --metrics-addr=localhost:9090)
• Disable the metrics service via the flag (e.g. --metrics-enabled=false)
• Adopt one of the recommended deployment models: Authzed’s managed services or the SpiceDB Operator

References

• GitHub Security Advisory issued for SpiceDB
• Go issue #22085 for documenting the risks of exposing pprof to the internet
• Go issue #42834 discusses preventing pprof registration to the default serve mux
• semgrep rule go.lang.security.audit.net.pprof.pprof-debug-exposure checks for a variation of this issue