Detection rules › Sigma
Ingress/Egress Security Group Modification
Detects when an account makes changes to the ingress or egress rules of a security group. This can indicate that an attacker is attempting to open up new attack vectors in the account, that they are trying to exfiltrate data over the network, or that they are trying to allow machines in that VPC/Subnet to contact a C&C server.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1190 Exploit Public-Facing Application |
Event coverage
Rules detecting the same action
Other rules on this platform that filter on the same API call or operation.
Rule body yaml
title: Ingress/Egress Security Group Modification
id: 6fb77778-040f-4015-9440-572aa9b6b580
status: test
description: |
Detects when an account makes changes to the ingress or egress rules of a security group.
This can indicate that an attacker is attempting to open up new attack vectors in the account, that they are trying to exfiltrate data over the network, or that they are trying to allow machines in that VPC/Subnet to contact a C&C server.
references:
- https://www.gorillastack.com/blog/real-time-events/important-aws-cloudtrail-security-events-tracking/
author: jamesc-grafana
date: 2024-07-11
tags:
- attack.initial-access
- attack.t1190
logsource:
product: aws
service: cloudtrail
detection:
selection:
eventSource: 'ec2.amazonaws.com'
eventName:
- 'AuthorizeSecurityGroupEgress'
- 'AuthorizeSecurityGroupIngress'
- 'RevokeSecurityGroupEgress'
- 'RevokeSecurityGroupIngress'
condition: selection
falsepositives:
- New VPCs and Subnets being setup requiring a different security profile to those already defined
- A single port being opened for a new service that is known to be deploying
- Administrators closing unused ports to reduce the attack surface
level: medium
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
eventSource: 'ec2.amazonaws.com'
eventName:
- 'AuthorizeSecurityGroupEgress'
- 'AuthorizeSecurityGroupIngress'
- 'RevokeSecurityGroupEgress'
- 'RevokeSecurityGroupIngress'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
eventName | eq |
|
eventSource | eq |
|