重要度別にGuardDutyをSlackに通知してみた

lib/sns-stack.ts

import { Stack, StackProps } from "aws-cdk-lib";
import { Construct } from "constructs";
import * as sns from "aws-cdk-lib/aws-sns";

export interface props extends StackProps {
  projectName: String;
  envName: String;
}

export class SnsStack extends Stack {
  public readonly snsTopicForHigh: sns.ITopic;
  public readonly snsTopicForMiddleLow: sns.ITopic;

  constructor(scope: Construct, id: string, props: props) {
    super(scope, id, props);

    /**
      *  Create a SNS for the eventbridge
      */
    this.snsTopicForHigh = new sns.Topic(this, `${props.projectName}-${props.envName}-for-guardduty-high`, {
      topicName: `${props.projectName}-${props.envName}-for-guardduty-high`,
      displayName: `${props.projectName}-${props.envName}-for-guardduty-high`,
    });

    this.snsTopicForMiddleLow = new sns.Topic(this, `${props.projectName}-${props.envName}-for-guardduty-middle-low`, {
      topicName: `${props.projectName}-${props.envName}-for-guardduty-middle`,
      displayName: `${props.projectName}-${props.envName}-for-guardduty-middle`,
    });
  }i
}

lib/lambda-stack.ts

import * as path from "path";

import { Stack, StackProps } from "aws-cdk-lib";
import { Construct } from "constructs";
import * as iam from "aws-cdk-lib/aws-iam";
import * as lambda from "aws-cdk-lib/aws-lambda";
import * as sns from "aws-cdk-lib/aws-sns";

export interface props extends StackProps {
  projectName: String;
  envName: String;
  snsTopicForHigh: sns.ITopic;
  snsTopicForMiddleLow: sns.ITopic;
}

export class LambdaStack extends Stack {
  public readonly lambdaFunction: lambda.IFunction;

  constructor(scope: Construct, id: string, props: props) {
    super(scope, id, props);

    /**
      * Create a Role
      */
    const role = new iam.Role(this, `${props.projectName}-${props.envName}-role`, {
      assumedBy: new iam.ServicePrincipal("lambda.amazonaws.com"),
    });
    role.addManagedPolicy(iam.ManagedPolicy.fromAwsManagedPolicyName("AmazonSNSFullAccess"));
    role.addManagedPolicy(
      iam.ManagedPolicy.fromManagedPolicyArn(
        this,
        `${props.projectName}-${props.envName}-lambdabasic`,
        "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
      )
    );

    /**
      *  Create a Lambda
      */
    this.lambdaFunction = new lambda.Function(this, `${props.projectName}-${props.envName}-lambda`, {
      functionName: `${props.projectName}-${props.envName}-lambda`,
      runtime: lambda.Runtime.PYTHON_3_9,
      handler: "lambda_function.lambda_handler",
      environment: {
        SNS_TOPIC_ARN_HIGH: props.snsTopicForHigh.topicArn,
        SNS_TOPIC_ARN_MIDDLE_LOW: props.snsTopicForMiddleLow.topicArn,
      },
      code: lambda.Code.fromAsset(path.join(__dirname, "./assets")),
      role: role,
    });
  }
}

/lib/indeeventbridge-stack.ts

import { Stack, StackProps } from "aws-cdk-lib";
import { Construct } from "constructs";
import * as events from "aws-cdk-lib/aws-events";
import * as targets from "aws-cdk-lib/aws-events-targets";
import * as lambda from "aws-cdk-lib/aws-lambda";

export interface props extends StackProps {
  projectName: String;
  envName: String;
  lambdaFunction: lambda.IFunction;
}

export class EventBridgeStack extends Stack {
  constructor(scope: Construct, id: string, props: props) {
    super(scope, id, props);

    /**
      *  Create a EventBridge
      */
    const rule = new events.Rule(this, `${props.projectName}-${props.envName}-events-rule`, {
      ruleName: `${props.projectName}-${props.envName}-events-rule`,
      eventPattern: {
        source: ["aws.guardduty"],
        detailType: ["GuardDuty Finding"],
      },
      targets: [new targets.LambdaFunction(props.lambdaFunction)],
    });
  }
}

/lib/chatbot-stack.ts

import { Stack, StackProps } from "aws-cdk-lib";
import { Construct } from "constructs";
import * as chatbot from "aws-cdk-lib/aws-chatbot";
import * as sns from "aws-cdk-lib/aws-sns";

export interface props extends StackProps {
  projectName: String;
  envName: String;
  snsTopicForHigh: sns.ITopic;
  snsTopicForMiddleLow: sns.ITopic;
  slackWorkspaceId: string;
  slackChannelId1: string;
  slackChannelId2: string;
}

export class ChatBotStack extends Stack {
  constructor(scope: Construct, id: string, props: props) {
    super(scope, id, props);

    /**
     *  Create a Chatbot
     */
    const slackChannel1 = new chatbot.SlackChannelConfiguration(this, `${props.projectName}-${props.envName}-guardduty-high`, {
      slackChannelConfigurationName: "guardduty-high",
      slackWorkspaceId: props.slackWorkspaceId,
      slackChannelId: props.slackChannelId1,
      notificationTopics: [props.snsTopicForHigh],
    });

    const slackChannel2 = new chatbot.SlackChannelConfiguration(this, `${props.projectName}-${props.envName}-guardduty-middle-low`, {
      slackChannelConfigurationName: "guardduty-middle-low",
      slackWorkspaceId: props.slackWorkspaceId,
      slackChannelId: props.slackChannelId2,
      notificationTopics: [props.snsTopicForMiddleLow],
    });
  }
}