Check for Unrestricted SQL Server Access

ID: gcloud-unrestricted-sqlserver-access

Severity: critical

Author: princechaddha

Tags: cloud,devops,gcp,gcloud,vpc,firewall,security,sqlserver,gcp-cloud-config

Description

Ensure that Google Cloud VPC network firewall rules do not allow unrestricted access (0.0.0.0/0 on TCP port 1433). Restrict access to trusted IP addresses or ranges to implement the Principle of Least Privilege (POLP) and reduce the attack surface.

YAML Source

id: gcloud-unrestricted-sqlserver-access

info:
  name: Check for Unrestricted SQL Server Access
  author: princechaddha
  severity: critical
  description: |
    Ensure that Google Cloud VPC network firewall rules do not allow unrestricted access (0.0.0.0/0 on TCP port 1433). Restrict access to trusted IP addresses or ranges to implement the Principle of Least Privilege (POLP) and reduce the attack surface.
  impact: |
    Allowing unrestricted access to TCP port 1433 exposes your resources to potential brute-force or unauthorized access attacks on SQL Server.
  remediation: |
    Update your VPC firewall rules to allow SQL Server traffic only from trusted IP addresses or ranges.
  reference:
    - https://cloud.google.com/vpc/docs/firewalls
  tags: cloud,devops,gcp,gcloud,vpc,firewall,security,sqlserver,gcp-cloud-config

flow: |
  code(1)
  for(let projectId of iterate(template.projectIds)){
    set("projectId", projectId)
    code(2)
    for(let networkName of iterate(template.networks)){
      set("networkName", networkName)
      code(3)
      set("firewallRules", template.firewallRules)
      javascript(1)
    }
  }

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 compute networks list --project $projectId --format="json(name)"

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

  - engine:
      - sh
      - bash
    source: |
      gcloud compute firewall-rules list --filter network=$networkName --sort-by priority --format="json(name,disabled,direction,sourceRanges,allowed[].ports)"

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

javascript:
  - code: |
      let firewallRules = template.firewallRules;
      if (typeof firewallRules === "string") {
          firewallRules = JSON.parse(firewallRules);
      }

      let unrestrictedSQLRules = [];
      for (let rule of firewallRules) {
          if (
              rule.disabled === false &&
              rule.direction === "INGRESS" &&
              Array.isArray(rule.sourceRanges) && rule.sourceRanges.includes("0.0.0.0/0") &&
              Array.isArray(rule.allowed) &&
              rule.allowed.some(allowed =>
                  Array.isArray(allowed.ports) &&
                  (allowed.ports.includes("1433"))
              )
          ) {
              unrestrictedSQLRules.push(rule.name);
          }
      }

      if (unrestrictedSQLRules.length > 0) {
          Export(`The firewall rules in network ${template.networkName} of project ${template.projectId} allow unrestricted SQL Server access: ${unrestrictedSQLRules.join(", ")}`);
      }

    extractors:
      - type: dsl
        dsl:
          - response
# digest: 4b0a00483046022100bb924f1b8a6c25951751348d9dbb93ae7630ff44fdd66dde03290b6f3b0e75de022100eb3fb94653b4eb69d8bb8d37906aea3b50c525fb22575b9adf9f37a15124d6ec: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/vpc/gcloud-unrestricted-sqlserver-access.yaml"

View on Github