Unrestricted access to port 3389
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Unrestricted access to port 3389

ec2

Classification:

compliance

Set up the ec2 integration.

Overview

Description

Reduce the probability of a breach by checking EC2 security groups for inbound rules that allow unfettered access to TCP port 3389 (used to connect a remote Remote Desktop Protocol (RDP) client application with an RDP server) and restrict access to IP addresses that require this port.

Rationale

Malicious activity, such as pass-the-hash (PtH) and man-in-the-middle attacks (MITM), can occur when permitting unfettered access to this port.

Remediation

See the CIS AWS Foundations Benchmark controls docs for console remediation steps.

  1. Run revoke-security-group-ingress to remove inbound rules that allow unrestricted access to port 3389.

    revoke-security-group-ingress.sh

       aws ec2 revoke-security-group-ingress
       --group-name group-name
       --protocol tcp
       --port 3389
       --cidr 192.0.2.0/24
       
  2. Run authorize-security-group-ingress to add new inbound rules that restrict port 3389 access.

    revoke-security-group-ingress.sh

       aws ec2 authorize-security-group-ingress
       --group-name your-group-name
       --protocol tcp
       --port 3389
       --cidr 192.0.2.0/24