Drata validates that no network access control lists (NACLs) allows unrestricted ingress access (source 0.0.0.0/0) to remote server administration ports, such as port 22 and port 3389, by checking each NACL’s inbound rules.
The Network Access Control List (NACL) function provide stateless filtering of ingress and egress network traffic to AWS resources. It is recommended that no NACL allows unrestricted ingress access to remote server administration ports, such as SSH to port22 and RDP to port 3389, using either the TDP (6), UDP (17) or ALL (-1) protocols.
Public access to remote server administration ports, such as 22 and 3389, increases resource attack surface and unnecessarily raises the risk of resource compromise.
ASSOCIATED DRATA CONTROL
This test is part of the Access to Remote Server Administration Ports Restricted control (DCF-73) that network security controls are in place to restrict public access to remote server administration ports (e.g., SSH, RDP) to authorized IP addresses or address ranges only.
WHAT TO DO IF A TEST FAILS
If Drata find that one or more network access control lists (NACLs) allows unrestricted ingress access (0.0.0.0/0) to remote server administration ports (22 or 3389), the test will fail.
Public access to remote server administration ports, such as 22 and 3389, increases resource attack surface and unnecessarily raises the risk of resource compromise.
STEPS TO REMEDIATE
Under the "Network ACLs" from the AWS Management Console:
Select the NACL that is failing this test and review its inbound allow and deny rules.
Make sure that ports 22 and 3389 are not allowing unrestricted access from undefined sources.
When reviewing allow and deny rules, note that AWS evaluates rules in their numerical order.
Center for Internet Security (CIS)
This test aligns with the Center for Internet Security’s (CIS) foundation benchmarks which provides prescriptive guidance for establishing a secure baseline configuration for Amazon Web Services. To learn more, refer to the Center for Internet Security (CIS) section.