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DoS vulnerability in otelgrpc (uncontrolled resource consumption) due to unbound cardinality metrics

High
pellared published GHSA-8pgv-569h-w5rw Nov 10, 2023

Package

gomod go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc (Go)

Affected versions

< 0.46.0

Patched versions

0.46.0

Description

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.addr
  • net.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

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE ID

CVE-2023-47108

Weaknesses

No CWEs