ec2-unrestricted-ftp: Restrict EC2 FTP Access

id: ec2-unrestricted-ftp
info:
  name: Restrict EC2 FTP Access
  author: princechaddha
  severity: critical
  description: |
    Ensure Amazon EC2 security groups disallow unrestricted inbound FTP access on TCP ports 20 and 21 to prevent brute force attacks.
  impact: |
    Unrestricted FTP access can expose EC2 instances to unauthorized access and brute force attacks, compromising security.
  remediation: |
    Restrict inbound access on TCP ports 20 and 21 for EC2 security groups to known IPs or remove the rules if FTP is not required.
  reference:
    - https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-network-security.html#security-group-rules
  tags: cloud,devops,aws,amazon,ec2,aws-cloud-config

variables:
  region: "us-east-1"

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: |
      aws ec2 describe-security-groups --region $region --filters Name=ip-permission.from-port,Values=20,21 Name=ip-permission.to-port,Values=20,21 Name=ip-permission.cidr,Values='0.0.0.0/0' --output json --query 'SecurityGroups[*].GroupId'

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

      - type: dsl
        dsl:
          - 'securitygroup + " security group(s) alows unrestricted access (0.0.0.0/0 or ::/0) on TCP port 20 or 21"'
# digest: 4b0a0048304602210099cdfad1028ecd96b255e64daac8277a337b818477a9657029246e6bef352cbc022100fe7cd54009ac03eb7d34820acbcec4894d9c77ccffeefb02733dce108a7b567b:922c64590222798bb761d5b6d8e72950