RDS security group allows broad CIDR ingress (broader than /16)

Severity: High
Service: RDS
Check ID: RDS_WIDE_CIDR_SECURITY_GROUP

What this check finds

A security group attached to this RDS instance allows inbound access from a CIDR range broader than /16, exposing the database port to a large address space.

Passing looks like: RDS security group scoped to a narrow CIDR.

How to fix it

Restrict the security group ingress rule to specific application subnets or VPC CIDR.

AWS CLI

aws ec2 revoke-security-group-ingress --group-id SG_ID --protocol tcp --port PORT --cidr WIDE_CIDR

Then allow the tighter range:

aws ec2 authorize-security-group-ingress --group-id SG_ID --protocol tcp --port PORT --cidr TIGHTER_CIDR

Names in capitals are placeholders for your own resource. Review a command before you run it.

AWS console

EC2 → Security Groups → Edit inbound rules.

Compliance controls it is evidence for

A failing result counts against these controls in KloudLytics; a passing one is evidence towards them. How compliance mapping works

Compliance controls mapped to RDS security group allows broad CIDR ingress (broader than /16)
Framework	Controls
PCI-DSS v4.0.1	1.3 Network access to and from the cardholder data environment is restricted
NIST SP 800-53 Rev5 (Moderate)	SC-7 Boundary Protection
NIST Cybersecurity Framework 2.0	PR.IR-01 Networks and environments are protected from unauthorized logical access and usage
ISO/IEC 27001:2022 Annex A	A.8.20 Networks security

Checked on every scan

KloudLytics runs this check each time it scans a connected AWS account, through a read-only role, and lists every affected resource with its region. On Pro and Business a fix is written for the specific resource rather than the general case above. The exact access it needs

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