mitigations.md

Mitigation Strategies Analysis for micro/go-micro

Mitigation Strategy: Enforce Mutual TLS (mTLS) via go-micro Configuration

MITIGATION STRATEGIES: Okay, here's the updated list of mitigation strategies, focusing exclusively on those that directly involve go-micro specific configurations, APIs, or features. I've removed strategies that are primarily about securing external dependencies (like the registry or broker) and kept only those where go-micro itself is the primary point of configuration.

go-micro Specific Mitigation Strategies

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1. Enforce Mutual TLS (mTLS) via go-micro Configuration

• Mitigation Strategy: Enforce mutual TLS (mTLS) for all inter-service communication using go-micro's built-in TLS support.

• Description:

  1. Certificate Authority (CA): Have a trusted CA (you still need this, but it's not a go-micro specific task).
  2. Certificate Generation: Generate client and server certificates for each service (again, not go-micro specific).
  3. go-micro Client Configuration: When creating a go-micro client, use the transport.TLSConfig option:

     import (
         "crypto/tls"
         "github.com/micro/go-micro/v2/client"
         "github.com/micro/go-micro/v2/transport"
     )
     
     // Load client certificate, key, and CA certificate
     cert, err := tls.LoadX509KeyPair("client.crt", "client.key")
     caCertPool := // ... load CA cert ...
     
     tlsConfig := &tls.Config{
         Certificates: []tls.Certificate{cert},
         RootCAs:      caCertPool,
     }
     
     c := client.NewClient(
         client.Transport(transport.NewTransport(transport.TLSConfig(tlsConfig))),
     )

  4. go-micro Server Configuration: When creating a go-micro server, use the transport.TLSConfig option and set ClientAuth to tls.RequireAndVerifyClientCert:

     import (
         "crypto/tls"
         "github.com/micro/go-micro/v2/server"
         "github.com/micro/go-micro/v2/transport"
     )
     
     // Load server certificate, key, and CA certificate
     cert, err := tls.LoadX509KeyPair("server.crt", "server.key")
     caCertPool := // ... load CA cert ...
     
     tlsConfig := &tls.Config{
         Certificates: []tls.Certificate{cert},
         ClientAuth:   tls.RequireAndVerifyClientCert, // Enforce mTLS
         ClientCAs:    caCertPool,
     }
     
     s := server.NewServer(
         server.Transport(transport.NewTransport(transport.TLSConfig(tlsConfig))),
     )

  5. Consistent Application: Ensure all go-micro clients and servers within your application are configured this way.

• Threats Mitigated:

  • Man-in-the-Middle (MITM) Attacks (High Severity): Prevents attackers from intercepting or modifying communication.
  • Service Impersonation (High Severity): Ensures only authorized services can communicate.
  • Data Eavesdropping (High Severity): Protects sensitive data in transit.

• Impact:

  • MITM Attacks: Risk significantly reduced (from High to Low).
  • Service Impersonation: Risk significantly reduced (from High to Low).
  • Data Eavesdropping: Risk significantly reduced (from High to Low).

• Currently Implemented:

  • Basic TLS is used in some services, but mTLS is not consistently enforced via go-micro configuration.

• Missing Implementation:

  • ClientAuth: tls.RequireAndVerifyClientCert is not set on all go-micro servers.
  • All clients are not configured with client certificates and the CA.

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Mitigation Strategy: Implement Rate Limiting using go-micro Middleware

2. Implement Rate Limiting using go-micro Middleware

• Mitigation Strategy: Implement rate limiting using go-micro's middleware capabilities.

• Description:

  1. Choose a Rate Limiting Library: Select a Go rate limiting library (e.g., github.com/uber-go/ratelimit, golang.org/x/time/rate).
  2. Create Middleware: Write go-micro middleware that wraps your service handlers and applies rate limiting:

     import (
         "context"
         "github.com/micro/go-micro/v2/server"
         "github.com/uber-go/ratelimit" // Example library
     )
     
     func RateLimitMiddleware(rl ratelimit.Limiter) server.HandlerWrapper {
         return func(fn server.HandlerFunc) server.HandlerFunc {
             return func(ctx context.Context, req server.Request, rsp interface{}) error {
                 rl.Take() // Blocks until a token is available
                 return fn(ctx, req, rsp)
             }
         }
     }

  3. Apply Middleware: Apply the middleware when creating your go-micro server:

     import (
         "github.com/micro/go-micro/v2"
         "github.com/micro/go-micro/v2/server"
     	"github.com/uber-go/ratelimit"
     )
     
     func main() {
         // Create a rate limiter (example)
     	rl := ratelimit.New(100) // 100 requests per second
     
         service := micro.NewService(
             micro.Name("my.service"),
             micro.WrapHandler(RateLimitMiddleware(rl)), // Apply the middleware
         )
     
         // ... register handlers ...
     
         if err := service.Run(); err != nil {
             // ... handle error ...
         }
     }

  4. Customize: Adjust the rate limiting logic (e.g., per-client limits, different limits for different endpoints) within your middleware. You might use the req.Method() or information from the ctx to make these decisions.
  5. Error Handling: Ensure your middleware properly handles the case where the rate limit is exceeded, returning an appropriate error (e.g., a 429 status code). go-micro will propagate this error back to the client.

• Threats Mitigated:

  • Denial-of-Service (DoS) Attacks (High Severity): Limits the rate of requests, preventing overload.
  • Resource Exhaustion (Medium Severity): Protects against excessive resource consumption.
  • Brute-Force Attacks (Medium Severity): Can slow down brute-force attempts.

• Impact:

  • DoS Attacks: Risk significantly reduced (from High to Medium).
  • Resource Exhaustion: Risk reduced (from Medium to Low).
  • Brute-Force Attacks: Risk reduced (from Medium to Low).

• Currently Implemented:

  • No go-micro middleware for rate limiting is currently implemented.

• Missing Implementation:

  • The RateLimitMiddleware and its integration with micro.WrapHandler are not present in any service.

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Mitigation Strategy: Secure Codec Usage and Custom Codec Validation

3. Secure Codec Usage and Custom Codec Validation

• Mitigation Strategy: Use secure codecs and, if using custom codecs, implement rigorous input validation and sanitization within the codec itself.

• Description:

  1. Prefer Standard Codecs: Use go-micro's built-in support for standard codecs like json and protobuf:

     import (
         "github.com/micro/go-micro/v2"
         "github.com/micro/go-micro/v2/codec/json" // Or codec/proto
     )
     
     service := micro.NewService(
         micro.Name("my.service"),
         micro.Codec("application/json", json.NewCodec), // Use JSON codec
     )

  2. Avoid Custom Codecs (If Possible): Minimize the use of custom codecs unless absolutely necessary.
  3. Custom Codec Validation (If Necessary): If you must create a custom codec, implement thorough input validation and sanitization within the ReadBody and WriteBody methods of the codec.Codec interface.
     • ReadBody: Before unmarshaling data, validate the raw byte stream. Check for unexpected characters, excessive lengths, or any patterns that could indicate an attack.
     • WriteBody: Before marshaling data, sanitize the data to ensure it doesn't contain any malicious content. This might involve escaping special characters or removing potentially harmful elements.
     • Error Handling: Return clear and specific errors if validation fails.
  4. Strict Schema: If possible, define a strict schema for your data (e.g., using Protobuf) and enforce it during serialization and deserialization.

• Threats Mitigated:

  • Code Injection (High Severity): Prevents vulnerabilities in custom codecs from being exploited.
  • Data Corruption (Medium Severity): Ensures data integrity.
  • Denial of Service (DoS) (Medium Severity): Prevents malformed data from causing crashes or resource exhaustion.

• Impact:

  • Code Injection: Risk reduced (from High to Medium).
  • Data Corruption: Risk reduced (from Medium to Low).
  • Denial of Service (DoS): Risk reduced (from Medium to Low).

• Currently Implemented:

  • The application primarily uses the standard json codec.

• Missing Implementation:

  • No custom codecs are currently in use, so no specific validation is missing. However, if custom codecs are introduced in the future, this strategy must be followed.

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Mitigation Strategy: Service Registration Validation (Custom Registry)

4. Service Registration Validation (Custom Registry)

• Mitigation Strategy: Implement custom service registration validation using a custom go-micro Registry implementation.

• Description:

  1. Create a Custom Registry: Implement the registry.Registry interface. This interface defines methods like Register, Deregister, GetService, and ListServices.
  2. Implement Validation Logic: Within your custom Register method, add logic to validate the service being registered. This could involve:
     • Source IP Check: Verify the IP address of the registration request against a whitelist or known network range.
     • Token/Signature Verification: Require the service to provide a valid token or digital signature during registration.
     • Service Name Whitelist: Only allow registration of services with names that match a predefined whitelist.
     • Metadata Inspection: Examine the service.Metadata for specific keys and values that indicate a trusted service.
  3. Wrap Existing Registry: You can wrap an existing registry (e.g., the default Consul registry) within your custom registry to reuse its functionality:

     import (
         "github.com/micro/go-micro/v2/registry"
         "github.com/micro/go-micro/v2/registry/consul" // Example
     )
     
     type ValidatingRegistry struct {
         registry.Registry
     }
     
     func (v *ValidatingRegistry) Register(s *registry.Service, opts ...registry.RegisterOption) error {
         // 1. Perform validation checks on 's' (the service being registered)
         if !isValid(s) {
             return errors.New("service registration failed validation")
         }
     
         // 2. If valid, delegate to the wrapped registry
         return v.Registry.Register(s, opts...)
     }
     
     // ... implement other registry.Registry methods, delegating to v.Registry ...
     
     func NewValidatingRegistry(opts ...registry.Option) registry.Registry {
         // Create a Consul registry (or any other)
         consulRegistry := consul.NewRegistry(opts...)
     
         // Wrap it with our validating registry
         return &ValidatingRegistry{Registry: consulRegistry}
     }

  4. Use the Custom Registry: When creating your go-micro service, specify your custom registry:

     import "github.com/micro/go-micro/v2"
     
     func main() {
         // Create your custom registry
         valRegistry := NewValidatingRegistry()
     
         service := micro.NewService(
             micro.Name("my.service"),
             micro.Registry(valRegistry), // Use the custom registry
         )
     
         // ...
     }

• Threats Mitigated:

  • Malicious Service Registration (High Severity): Prevents unauthorized services from joining the network.
  • Rogue Service Injection (High Severity): Adds a layer of defense against attackers injecting malicious services.

• Impact:

  • Malicious Service Registration: Risk significantly reduced (from High to Low).
  • Rogue Service Injection: Risk significantly reduced (from High to Low).

• Currently Implemented:

  • Not implemented. The default Kubernetes registry is used.

• Missing Implementation:

  • The entire ValidatingRegistry implementation and its integration with micro.Registry are missing.

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These four strategies are directly tied to go-micro's API and configuration, providing the most focused approach to mitigating threats specifically arising from the framework's use. They represent the core go-micro specific security controls.