Sigma rule: LoadBalancer Security Group Modification

Rule

Title

LoadBalancer Security Group Modification

Status

test

Level

medium

Author

jamesc-grafana

Date

2024-07-11

File

rules/cloud/aws/cloudtrail/aws_cloudtrail_security_group_change_loadbalancer.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects changes to the security groups associated with an Elastic Load Balancer (ELB) or Application Load Balancer (ALB).
This can indicate that a misconfiguration allowing more traffic into the system than required, or could indicate that an attacker is attempting to enable new connections into a VPC or subnet controlled by the account.

Log source

product

aws

service

cloudtrail

Detection

selection:
    eventSource: 'elasticloadbalancing.amazonaws.com'
    eventName:
        - 'ApplySecurityGroupsToLoadBalancer'
        - 'SetSecurityGroups'
condition: selection

False positives (as the rule lists them)

• Repurposing of an ELB or ALB to serve a different or additional application
• Changes to security groups to allow for new services to be deployed

Tags

• attack.initial-access
• attack.t1190

MITRE ATT&CK ids this rule names

• T1190

References

• https://www.gorillastack.com/blog/real-time-events/important-aws-cloudtrail-security-events-tracking/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/cloud/aws/cloudtrail/aws_cloudtrail_security_group_change_loadbalancer.yml