No Serverless VPC Access in Google Cloud Functions

ID: gcloud-func-no-vpc-access

Severity: high

Author: princechaddha

Tags: cloud,devops,gcp,gcloud,google-cloud-functions,gcp-cloud-config

Description

Ensure that your Google Cloud functions are configured to use Serverless VPC Access in order to connect functions directly to your VPC network, allowing access to other VPC resources such as VM instances, MemoryStore instances, or any other cloud resources with an internal IP address. Without Serverless VPC Access, these functions may not be able to communicate efficiently with other resources in the same VPC.

YAML Source

id: gcloud-func-no-vpc-access

info:
  name: No Serverless VPC Access in Google Cloud Functions
  author: princechaddha
  severity: high
  description: |
    Ensure that your Google Cloud functions are configured to use Serverless VPC Access in order to connect functions directly to your VPC network, allowing access to other VPC resources such as VM instances, MemoryStore instances, or any other cloud resources with an internal IP address. Without Serverless VPC Access, these functions may not be able to communicate efficiently with other resources in the same VPC.
  impact: |
    Lack of Serverless VPC Access in Google Cloud functions can lead to inefficient or failed communications between your serverless functions and other resources within the same VPC, impacting application performance and increasing latency.
  remediation: |
    Configure Serverless VPC Access for your Google Cloud functions by setting the vpcConnector parameter to the name of an already configured VPC connector in your project settings.
  reference:
    - https://cloud.google.com/functions/docs/connecting-vpc
  tags: cloud,devops,gcp,gcloud,google-cloud-functions,gcp-cloud-config

flow: |
  code(1)
  for(let projectId of iterate(template.projectIds)){
    set("projectId", projectId)
    code(2)
    for(let functionName of iterate(template.functions)){
      set("functionName", functionName)
      code(3)
    }
  }

self-contained: true

code:
  - engine:
      - sh
      - bash
    source: |
      gcloud projects list --format="json(projectId)"

    extractors:
      - type: json
        name: projectIds
        internal: true
        json:
          - '.[].projectId'

  - engine:
      - sh
      - bash
    source: |
      gcloud functions list --project $projectId --format="json(name)"

    extractors:
      - type: json
        name: functions
        internal: true
        json:
          - '.[].name'

  - engine:
      - sh
      - bash
    source: |
      gcloud functions describe $functionName --region=us-central1 --format="json(vpcConnector)"

    matchers:
      - type: word
        words:
          - 'null'

    extractors:
      - type: dsl
        dsl:
          - '"No Serverless VPC Access in function: " + functionName + " in " + projectId + " project"'
# digest: 4a0a004730450220397c7cc5e8bbd815dc87d42001c3d67f3ad2a5472ae673d8a30ae79533a5298d0221009dc8716a28b3dbf002ecacb0ea76d8df3890c5fa966d55041b173ea247e57cd4:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "cloud/gcp/function/gcloud-func-no-vpc-access.yaml"

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