ec2-unrestricted-ssh: Unrestricted SSH Access in EC2

id: ec2-unrestricted-ssh
info:
  name: Unrestricted SSH Access in EC2
  author: princechaddha
  severity: high
  description: |
    Checks for inbound rules in Amazon EC2 security groups that allow unrestricted SSH access (0.0.0.0/0 or ::/0) on TCP port 22, indicating a security risk by exposing the SSH server to the internet.
  impact: |
    Unrestricted SSH access increases the risk of unauthorized access and potential brute force attacks against the SSH server, compromising the security of the EC2 instances.
  remediation: |
    Restrict SSH access in EC2 security groups to trusted IP addresses or ranges, adhering to the Principle of Least Privilege (POLP) and mitigating the risk of unauthorized access.
  reference:
    - https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/security-group-rules-reference.html
  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=22 Name=ip-permission.to-port,Values=22 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 22"'
# digest: 4b0a00483046022100e8074eceea770759e675b6129efa00627dced989dcc885eb2be386f01e6e6f20022100ef26f24ef231e9d10f9f1e8309f5fa0e24068ba4560570a071c1e82b36c2bd28:922c64590222798bb761d5b6d8e72950