github.com/khulnasoft-lab/defsec@v1.0.5-0.20230827010352-5e9f46893d95/rules/cloud/policies/aws/ec2/enforce_http_token_imds.go (about)

     1  package ec2
     2  
     3  import (
     4  	"github.com/khulnasoft-lab/defsec/internal/rules"
     5  	"github.com/khulnasoft-lab/defsec/pkg/providers"
     6  	"github.com/khulnasoft-lab/defsec/pkg/scan"
     7  	"github.com/khulnasoft-lab/defsec/pkg/severity"
     8  	"github.com/khulnasoft-lab/defsec/pkg/state"
     9  )
    10  
    11  var CheckIMDSAccessRequiresToken = rules.Register(
    12  	scan.Rule{
    13  		AVDID:      "AVD-AWS-0028",
    14  		Provider:   providers.AWSProvider,
    15  		Service:    "ec2",
    16  		ShortCode:  "enforce-http-token-imds",
    17  		Summary:    "aws_instance should activate session tokens for Instance Metadata Service.",
    18  		Impact:     "Instance metadata service can be interacted with freely",
    19  		Resolution: "Enable HTTP token requirement for IMDS",
    20  		Explanation: `
    21  IMDS v2 (Instance Metadata Service) introduced session authentication tokens which improve security when talking to IMDS.
    22  By default <code>aws_instance</code> resource sets IMDS session auth tokens to be optional. 
    23  To fully protect IMDS you need to enable session tokens by using <code>metadata_options</code> block and its <code>http_tokens</code> variable set to <code>required</code>.
    24  `,
    25  
    26  		Links: []string{
    27  			"https://aws.amazon.com/blogs/security/defense-in-depth-open-firewalls-reverse-proxies-ssrf-vulnerabilities-ec2-instance-metadata-service",
    28  		},
    29  
    30  		Terraform: &scan.EngineMetadata{
    31  			GoodExamples:        terraformEnforceHttpTokenImdsGoodExamples,
    32  			BadExamples:         terraformEnforceHttpTokenImdsBadExamples,
    33  			Links:               terraformEnforceHttpTokenImdsLinks,
    34  			RemediationMarkdown: terraformEnforceHttpTokenImdsRemediationMarkdown,
    35  		},
    36  		Severity: severity.High,
    37  	},
    38  	func(s *state.State) (results scan.Results) {
    39  		for _, instance := range s.AWS.EC2.Instances {
    40  			if !instance.RequiresIMDSToken() && !instance.HasHTTPEndpointDisabled() {
    41  				results.Add(
    42  					"Instance does not require IMDS access to require a token",
    43  					instance.MetadataOptions.HttpTokens,
    44  				)
    45  			} else {
    46  				results.AddPassed(&instance)
    47  			}
    48  		}
    49  		return results
    50  	},
    51  )