Summary
The grpc Unary Server Interceptor opentelemetry-go-contrib/instrumentation/google.golang.org/grpc/otelgrpc/interceptor.go
// UnaryServerInterceptor returns a grpc.UnaryServerInterceptor suitable
// for use in a grpc.NewServer call.
func UnaryServerInterceptor(opts ...Option) grpc.UnaryServerInterceptor {
out of the box adds labels
net.peer.sock.addrnet.peer.sock.port
that have unbound cardinality. It leads to the server's potential memory exhaustion when many malicious requests are sent.
Details
An attacker can easily flood the peer address and port for requests.
PoC
Apply the attached patch to the example and run the client multiple times. Observe how each request will create a unique histogram and how the memory consumption increases during it.
Impact
In order to be affected, the program has to configure a metrics pipeline, use UnaryServerInterceptor, and does not filter any client IP address and ports via middleware or proxies, etc.
Others
It is similar to already reported vulnerabilities.
Workaround for affected versions
As a workaround to stop being affected, a view removing the attributes can be used.
The other possibility is to disable grpc metrics instrumentation by passing otelgrpc.WithMeterProvider option with noop.NewMeterProvider.
Solution provided by upgrading
In PR #4322, to be released with v0.46.0, the attributes were removed.
References
Summary
The grpc Unary Server Interceptor opentelemetry-go-contrib/instrumentation/google.golang.org/grpc/otelgrpc/interceptor.go
out of the box adds labels
net.peer.sock.addrnet.peer.sock.portthat have unbound cardinality. It leads to the server's potential memory exhaustion when many malicious requests are sent.
Details
An attacker can easily flood the peer address and port for requests.
PoC
Apply the attached patch to the example and run the client multiple times. Observe how each request will create a unique histogram and how the memory consumption increases during it.
Impact
In order to be affected, the program has to configure a metrics pipeline, use UnaryServerInterceptor, and does not filter any client IP address and ports via middleware or proxies, etc.
Others
It is similar to already reported vulnerabilities.
Workaround for affected versions
As a workaround to stop being affected, a view removing the attributes can be used.
The other possibility is to disable grpc metrics instrumentation by passing
otelgrpc.WithMeterProvideroption withnoop.NewMeterProvider.Solution provided by upgrading
In PR #4322, to be released with v0.46.0, the attributes were removed.
References