Control: 5.3 Ensure no security groups allow ingress from 0.0.0.0/0 to remote server administration ports

Description

Security groups provide stateful filtering of ingress and egress network traffic to AWS resources. It is recommended that no security group allows unrestricted ingress access to remote server administration ports, such as SSH on port 22 and RDP on port 3389, using either the TCP (6), UDP (17), or ALL (-1) protocols.

Public access to remote server administration ports, such as 22 (when used for SSH, not SFTP) and 3389, increases the attack surface of resources and unnecessarily raises the risk of resource compromise.

Remediation

Perform the following to implement the prescribed state:

Login to the AWS VPC Console at https://console.aws.amazon.com/vpc/home.
In the left pane, click Security Groups.
For each security group, perform the following:

Select the security group.
Click the Inbound Rules tab.
Click the Edit inbound rules button.
Identify the rules to be edited or removed.
Either A) update the Source field to a range other than 0.0.0.0/0, or B) click Delete to remove the offending inbound rule.
Click Save rules.

Usage

Run the control in your terminal:

powerpipe control run aws_compliance.control.cis_v400_5_3

Snapshot and share results via Turbot Pipes:

powerpipe login
powerpipe control run aws_compliance.control.cis_v400_5_3 --share

SQL

This control uses a named query:

with bad_rules as (
  select
    group_id,
    count(*) as num_bad_rules
  from
    aws_vpc_security_group_rule
  where
    type = 'ingress'
    and (
      cidr_ipv4 = '0.0.0.0/0'
      or cidr_ipv6 = '::/0'
    )
    and (
        ( ip_protocol = '-1'      -- all traffic
        and from_port is null
        )
        or (
            from_port <= 22
            and to_port >= 22
        )
        or (
            from_port <= 3389
            and to_port >= 3389
        )
    )
  group by
    group_id
),
security_groups as (
  select
    arn,
    tags,
    region,
    account_id,
    group_id,
    _ctx
  from
    aws_vpc_security_group
  order by
    group_id
)
select
  arn as resource,
  case
    when bad_rules.group_id is null then 'ok'
    else 'alarm'
  end as status,
  case
    when bad_rules.group_id is null then sg.group_id || ' does not allow ingress to port 22 or 3389 from 0.0.0.0/0 or ::/0.'
    else  sg.group_id || ' contains ' || bad_rules.num_bad_rules || ' rule(s) that allow ingress to port 22 or 3389 from 0.0.0.0/0 or ::/0.'
  end as reason
  
  , sg.region, sg.account_id
from
  security_groups as sg
  left join bad_rules on bad_rules.group_id = sg.group_id;

Control: 5.3 Ensure no security groups allow ingress from 0.0.0.0/0 to remote server administration ports

Description

Remediation

Usage

SQL

Tags