No CloudWatch alarm for security group changes

Severity: Medium
Service: Monitoring and alarms
Check ID: CLOUDWATCH_ALARM_SG_CHANGES

What this check finds

No metric filter and alarm detect security group rule modifications. Unauthorized SG changes can open unexpected network paths to sensitive resources. CIS v1.4 §4.10.

Passing looks like: CloudWatch alarm for security group changes configured.

How to fix it

Create a metric filter covering AuthorizeSecurityGroupIngress, AuthorizeSecurityGroupEgress, RevokeSecurityGroupIngress, RevokeSecurityGroupEgress, CreateSecurityGroup, DeleteSecurityGroup events.

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 No CloudWatch alarm for security group changes
Framework	Controls
CIS AWS Foundations Benchmark v5.0.0	4.10 Ensure security group changes are monitored
NIST SP 800-53 Rev5 (Moderate)	AU-6 Audit Record Review, Analysis, and Reporting SC-7 Boundary Protection SI-4 System Monitoring
NIST Cybersecurity Framework 2.0	PR.IR-01 Networks and environments are protected from unauthorized logical access and usage DE.AE-02 Adverse events are analyzed DE.CM-01 Networks are monitored
ISO/IEC 27001:2022 Annex A	A.8.16 Monitoring activities 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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