New attack technique: Persistence AWS Lambda Layer Extension (#427)

* Add lambda-layer-extension technique

* build documentation

* Minor docs editing

* Minor code changes

---------

Co-authored-by: Christophe Tafani-Dereeper <christophe.tafanidereeper@datadoghq.com>

docs/attack-techniques/AWS/aws.persistence.iam-backdoor-user.md

@@ -29,6 +29,7 @@ Establishes persistence by creating an access key on an existing IAM user.
 - Create an IAM access key on the user.
 
 References:
+
 - https://sysdig.com/blog/scarleteel-2-0/
 
 

docs/attack-techniques/AWS/aws.persistence.iam-create-admin-user.md

@@ -29,6 +29,7 @@ Establishes persistence by creating a new IAM user with administrative permissio
 References:
 
 - https://permiso.io/blog/s/approach-to-detection-androxgh0st-greenbot-persistence/
+- https://permiso.io/blog/s/unmasking-guivil-new-cloud-threat-actor/
 - https://blog.darklab.hk/2021/07/06/trouble-in-paradise/
 - https://expel.com/blog/incident-report-from-cli-to-console-chasing-an-attacker-in-aws/
 

docs/attack-techniques/AWS/aws.persistence.iam-create-user-login-profile.md

@@ -30,7 +30,9 @@ user intended to be used programmatically through the AWS console usual login pr
 - Create an IAM Login Profile on the user
 
 References:
+
 - https://permiso.io/blog/s/approach-to-detection-androxgh0st-greenbot-persistence/
+- https://permiso.io/blog/s/unmasking-guivil-new-cloud-threat-actor/
 - https://blog.darklab.hk/2021/07/06/trouble-in-paradise/
 - https://expel.com/blog/incident-report-from-cli-to-console-chasing-an-attacker-in-aws/
 

docs/attack-techniques/AWS/aws.persistence.lambda-layer-extension.md

@@ -0,0 +1,51 @@
+---
+title: Add a Malicious Lambda Extension
+---
+
+# Add a Malicious Lambda Extension
+
+
+ <span class="smallcaps w3-badge w3-blue w3-round w3-text-white" title="This attack technique can be detonated multiple times">idempotent</span> 
+
+Platform: AWS
+
+## MITRE ATT&CK Tactics
+
+
+- Persistence
+- Privilege Escalation
+
+## Description
+
+
+Establishes persistence by adding a malicious lambda extension.
+
+<span style="font-variant: small-caps;">Warm-up</span>: 
+
+- Create a Lambda function and a lambda extension (layer).
+
+<span style="font-variant: small-caps;">Detonation</span>: 
+
+- Add the extension as a layer to the Lambda function.
+
+References:
+
+- https://www.clearvector.com/blog/lambda-spy/
+
+
+## Instructions
+
+```bash title="Detonate with Stratus Red Team"
+stratus detonate aws.persistence.lambda-layer-extension
+```
+## Detection
+
+
+Through CloudTrail's <code>UpdateFunctionConfiguration20150331v2</code> event.
+
+While matching this event may be impractical and prone to false positives in most environments, the following can help to craft more precise detections:
+
+- Identify calls to <code>UpdateFunctionConfiguration20150331v2</code> where the <code>responseElements</code> field contains <code>layer</code>, indicating that the function's layers were modified.
+- Identify calls to <code>UpdateFunctionConfiguration20150331v2</code> where <code>responseElements.layers</code> includes a layer that's from a different AWS account.'
+
+

docs/attack-techniques/AWS/aws.persistence.lambda-overwrite-code.md

@@ -29,6 +29,7 @@ A further, more advanced, use-case could be updating the code to exfiltrate the
 - Update the Lambda function code.
 
 References:
+
 - https://research.splunk.com/cloud/aws_lambda_updatefunctioncode/
 - Expel's AWS security mindmap
 

docs/attack-techniques/AWS/index.md

@@ -87,6 +87,8 @@ Note that some Stratus attack techniques may correspond to more than a single AT
 
 - [Create an IAM Roles Anywhere trust anchor](./aws.persistence.rolesanywhere-create-trust-anchor.md)
 
+- [Add a Malicious Lambda Extension](./aws.persistence.lambda-layer-extension.md)
+
 
 ## Privilege Escalation
 
@@ -100,3 +102,5 @@ Note that some Stratus attack techniques may correspond to more than a single AT
 
 - [Create an IAM Roles Anywhere trust anchor](./aws.persistence.rolesanywhere-create-trust-anchor.md)
 
+- [Add a Malicious Lambda Extension](./aws.persistence.lambda-layer-extension.md)
+

docs/attack-techniques/GCP/gcp.persistence.create-admin-service-account.md

@@ -29,6 +29,7 @@ Establishes persistence by creating a new service account and assigning it
 - Update the current GCP project's IAM policy to bind the service account to the <code>owner</code> role'
 
 References:
+
 - https://about.gitlab.com/blog/2020/02/12/plundering-gcp-escalating-privileges-in-google-cloud-platform/
 
 

docs/attack-techniques/list.md

@@ -39,6 +39,7 @@ This page contains the list of all Stratus Attack Techniques.
 | [Backdoor Lambda Function Through Resource-Based Policy](./AWS/aws.persistence.lambda-backdoor-function.md) | [AWS](./AWS/index.md) | Persistence |
 | [Overwrite Lambda Function Code](./AWS/aws.persistence.lambda-overwrite-code.md) | [AWS](./AWS/index.md) | Persistence |
 | [Create an IAM Roles Anywhere trust anchor](./AWS/aws.persistence.rolesanywhere-create-trust-anchor.md) | [AWS](./AWS/index.md) | Persistence, Privilege Escalation |
+| [Add a Malicious Lambda Extension](./AWS/aws.persistence.lambda-layer-extension.md) | [AWS](./AWS/index.md) | Persistence, Privilege Escalation |
 | [Execute Command on Virtual Machine using Custom Script Extension](./azure/azure.execution.vm-custom-script-extension.md) | [Azure](./azure/index.md) | Execution |
 | [Execute Commands on Virtual Machine using Run Command](./azure/azure.execution.vm-run-command.md) | [Azure](./azure/index.md) | Execution |
 | [Export Disk Through SAS URL](./azure/azure.exfiltration.disk-export.md) | [Azure](./azure/index.md) | Exfiltration |

docs/index.yaml

@@ -222,6 +222,14 @@ AWS:
             - Privilege Escalation
           platform: AWS
           isIdempotent: false
+        - id: aws.persistence.lambda-layer-extension
+          name: Add a Malicious Lambda Extension
+          isSlow: false
+          mitreAttackTactics:
+            - Persistence
+            - Privilege Escalation
+          platform: AWS
+          isIdempotent: true
     Privilege Escalation:
         - id: aws.execution.ec2-user-data
           name: Execute Commands on EC2 Instance via User Data
@@ -263,6 +271,14 @@ AWS:
             - Privilege Escalation
           platform: AWS
           isIdempotent: false
+        - id: aws.persistence.lambda-layer-extension
+          name: Add a Malicious Lambda Extension
+          isSlow: false
+          mitreAttackTactics:
+            - Persistence
+            - Privilege Escalation
+          platform: AWS
+          isIdempotent: true
 GCP:
     Exfiltration:
         - id: gcp.exfiltration.share-compute-disk

v2/internal/attacktechniques/aws/persistence/lambda-layer-extension/main.go

@@ -0,0 +1,89 @@
+package aws
+
+import (
+	"context"
+	_ "embed"
+	"errors"
+	"log"
+
+	"github.com/aws/aws-sdk-go-v2/service/lambda"
+	"github.com/datadog/stratus-red-team/v2/pkg/stratus"
+	"github.com/datadog/stratus-red-team/v2/pkg/stratus/mitreattack"
+)
+
+//go:embed main.tf
+var tf []byte
+
+func init() {
+	stratus.GetRegistry().RegisterAttackTechnique(&stratus.AttackTechnique{
+		ID:           "aws.persistence.lambda-layer-extension",
+		FriendlyName: "Add a Malicious Lambda Extension",
+		Description: `
+Establishes persistence by adding a malicious lambda extension.
+
+Warm-up: 
+
+- Create a Lambda function and a lambda extension (layer).
+
+Detonation: 
+
+- Add the extension as a layer to the Lambda function.
+
+References:
+
+- https://www.clearvector.com/blog/lambda-spy/
+`,
+		Detection: `
+Through CloudTrail's <code>UpdateFunctionConfiguration20150331v2</code> event.
+
+While matching this event may be impractical and prone to false positives in most environments, the following can help to craft more precise detections:
+		
+- Identify calls to <code>UpdateFunctionConfiguration20150331v2</code> where the <code>responseElements</code> field contains <code>layer</code>, indicating that the function's layers were modified.
+- Identify calls to <code>UpdateFunctionConfiguration20150331v2</code> where <code>responseElements.layers</code> includes a layer that's from a different AWS account.'
+`,
+		Platform:                   stratus.AWS,
+		PrerequisitesTerraformCode: tf,
+		IsIdempotent:               true,
+		MitreAttackTactics:         []mitreattack.Tactic{mitreattack.Persistence, mitreattack.PrivilegeEscalation},
+		Detonate:                   detonate,
+		Revert:                     revert,
+	})
+}
+
+func detonate(params map[string]string, providers stratus.CloudProviders) error {
+	ctx := context.Background()
+	lambdaClient := lambda.NewFromConfig(providers.AWS().GetConnection())
+	lambdaExtensionLayerArn := params["lambda_extension_layer_arn"]
+	lambdaArn := params["lambda_arn"]
+
+	// Update the function configuration with our layer
+	_, err := lambdaClient.UpdateFunctionConfiguration(ctx, &lambda.UpdateFunctionConfigurationInput{
+		FunctionName: &lambdaArn,
+		Layers:       []string{lambdaExtensionLayerArn},
+	})
+
+	if err != nil {
+		return errors.New("unable to update function configuration: " + err.Error())
+	}
+
+	log.Println("Added simulated malicious layer to Lambda function ", lambdaArn)
+	return nil
+}
+
+func revert(params map[string]string, providers stratus.CloudProviders) error {
+	ctx := context.Background()
+	lambdaArn := params["lambda_arn"]
+	lambdaClient := lambda.NewFromConfig(providers.AWS().GetConnection())
+
+	// Update the function configuration with an empty list of layers
+	_, err := lambdaClient.UpdateFunctionConfiguration(ctx, &lambda.UpdateFunctionConfigurationInput{
+		FunctionName: &lambdaArn,
+		Layers:       []string{},
+	})
+
+	if err != nil {
+		return errors.New("unable to update function configuration: " + err.Error())
+	}
+	log.Printf("Layers have been removed from the Lambda function %s\n", lambdaArn)
+	return nil
+}

v2/internal/attacktechniques/aws/persistence/lambda-layer-extension/main.tf

@@ -0,0 +1,113 @@
+terraform {
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "~> 4.0"
+    }
+  }
+}
+provider "aws" {
+  skip_region_validation      = true
+  skip_credentials_validation = true
+  skip_get_ec2_platforms      = true
+  default_tags {
+    tags = {
+      StratusRedTeam = true
+    }
+  }
+}
+
+locals {
+  resource_prefix = "stratus-red-team-lambda-layer"
+}
+
+resource "aws_iam_role" "lambda_role" {
+  name = "${local.resource_prefix}-lambda-role"
+
+  assume_role_policy = jsonencode({
+    Version = "2012-10-17"
+    Statement = [
+      {
+        Action = "sts:AssumeRole"
+        Effect = "Allow"
+        Principal = {
+          "Service" : [
+            "lambda.amazonaws.com"
+          ]
+        }
+      },
+    ]
+  })
+}
+
+resource "aws_iam_policy" "lambda_logs" {
+  name        = "${local.resource_prefix}-lambda-logs"
+  description = "Allows Lambda function to write logs to CloudWatch"
+
+  policy = <<EOF
+{
+  "Version": "2012-10-17",
+  "Statement": [
+    {
+      "Action": [
+        "logs:CreateLogGroup",
+        "logs:CreateLogStream",
+        "logs:PutLogEvents"
+      ],
+      "Effect": "Allow",
+      "Resource": "*"
+    }
+  ]
+}
+EOF
+}
+
+resource "aws_iam_role_policy_attachment" "lambda_logs_attach" {
+  role       = aws_iam_role.lambda_role.name
+  policy_arn = aws_iam_policy.lambda_logs.arn
+}
+
+resource "aws_s3_bucket" "bucket" {
+  bucket        = "${local.resource_prefix}-bucket"
+  force_destroy = true
+}
+resource "aws_s3_bucket_object" "code" {
+  bucket         = aws_s3_bucket.bucket.id
+  key            = "simpleLambda.zip"
+  content_base64 = "UEsDBBQACAAIAAAAIYoAAAAAAAAAAAAAAAAPAAAAc2ltcGxlTGFtYmRhLnB5RIuxCgIxEAX7+4pntQpXHJZpbSws/IWcu8cJya4ke2IQ/11M43TDMCwL1qicpOzlKeojbqYuLz+EAQCK+FYU7y4/qHr0rZ6MhQKO0zT+02zcKIDOkpJhKZaRG+o9P5Lg2nw1xSXmmeOO+vUZvgEAAP//UEsHCCE/h3lyAAAAgQAAAFBLAQIUAxQACAAIAAAAIYohP4d5cgAAAIEAAAAPAAAAAAAAAAAAAACkgQAAAABzaW1wbGVMYW1iZGEucHlQSwUGAAAAAAEAAQA9AAAArwAAAAAA"
+}
+
+resource "aws_lambda_function" "lambda" {
+  s3_bucket     = aws_s3_bucket.bucket.id
+  s3_key        = aws_s3_bucket_object.code.key
+  function_name = "${local.resource_prefix}-simpleLambda"
+  role          = aws_iam_role.lambda_role.arn
+  handler       = "${local.resource_prefix}-simpleLambda.handler"
+  timeout       = 20
+
+  runtime = "python3.10"
+
+  publish = true
+}
+
+resource "aws_s3_bucket_object" "code_layer" {
+  bucket         = aws_s3_bucket.bucket.id
+  key            = "simpleLayer.zip"
+  content_base64 = "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"
+}
+
+resource "aws_lambda_layer_version" "lambda_extension_layer" {
+  s3_bucket     = aws_s3_bucket.bucket.id
+  s3_key        = aws_s3_bucket_object.code_layer.key
+  layer_name = "${local.resource_prefix}-my-lambda-extension"
+
+  compatible_runtimes = ["python3.10"]
+}
+
+output "lambda_extension_layer_arn" {
+  value = aws_lambda_layer_version.lambda_extension_layer.arn
+}
+
+output "lambda_arn" {
+  value = aws_lambda_function.lambda.arn
+}

v2/internal/attacktechniques/main.go

@@ -31,6 +31,7 @@ import (
 	_ "github.com/datadog/stratus-red-team/v2/internal/attacktechniques/aws/persistence/lambda-backdoor-function"
 	_ "github.com/datadog/stratus-red-team/v2/internal/attacktechniques/aws/persistence/lambda-overwrite-code"
 	_ "github.com/datadog/stratus-red-team/v2/internal/attacktechniques/aws/persistence/rolesanywhere-create-trust-anchor"
+	_ "github.com/datadog/stratus-red-team/v2/internal/attacktechniques/aws/persistence/lambda-layer-extension"
 	_ "github.com/datadog/stratus-red-team/v2/internal/attacktechniques/azure/execution/vm-custom-script-extension"
 	_ "github.com/datadog/stratus-red-team/v2/internal/attacktechniques/azure/execution/vm-run-command"
 	_ "github.com/datadog/stratus-red-team/v2/internal/attacktechniques/azure/exfiltration/disk-export"