Detect Disable or Modify Cloud Firewall in Google Chronicle
Adversaries may disable or modify a firewall within a cloud environment to bypass controls that limit access to cloud resources. Cloud environments typically utilize restrictive security groups and firewall rules that only allow network activity from trusted IP addresses via expected ports and protocols. An adversary with appropriate permissions may introduce new firewall rules or policies to allow access into a victim cloud environment. For example, adversaries may create new ingress rules in existing security groups or create new security groups entirely to allow any TCP/IP connectivity.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1562 Impair Defenses
- Sub-technique
- T1562.007 Disable or Modify Cloud Firewall
- Canonical reference
- https://attack.mitre.org/techniques/T1562/007/
YARA-L Detection Query
rule mitre_t1562_007_cloud_firewall_modification {
meta:
author = "Argus Detection Engineering"
description = "Detects modification, creation, or deletion of cloud firewall rules across AWS, Azure, and GCP that may indicate an adversary bypassing network access controls."
mitre_attack_tactic = "Defense Evasion"
mitre_attack_technique = "T1562.007"
severity = "HIGH"
priority = "HIGH"
events:
$e.metadata.event_type = "USER_RESOURCE_UPDATE_CONTENT"
(
(
$e.metadata.vendor_name = "AMAZON"
AND (
$e.metadata.product_event_type = "AuthorizeSecurityGroupIngress"
OR $e.metadata.product_event_type = "AuthorizeSecurityGroupEgress"
OR $e.metadata.product_event_type = "RevokeSecurityGroupIngress"
OR $e.metadata.product_event_type = "RevokeSecurityGroupEgress"
OR $e.metadata.product_event_type = "CreateSecurityGroup"
OR $e.metadata.product_event_type = "DeleteSecurityGroup"
)
)
OR (
$e.metadata.vendor_name = "MICROSOFT"
AND re.regex($e.target.resource.name, `(?i)networkSecurityGroups`)
)
OR (
$e.metadata.vendor_name = "GOOGLE"
AND re.regex($e.target.resource.name, `(?i)compute\.firewalls`)
)
)
condition:
$e
}Chronicle YARA-L 2.0 rule detecting cloud firewall configuration changes across AWS, Azure, and GCP using Unified Data Model fields. Triggers on security group ingress/egress authorization changes, NSG write operations, and GCP compute firewall modifications. Correlates actor identity via principal.user fields for analyst triage.
Data Sources
Required Tables
False Positives & Tuning
- Cloud-native network automation tools that programmatically manage firewall rules as part of service mesh or zero-trust network architecture implementations
- Disaster recovery drills that simulate environment reconstruction including firewall rule provisioning from infrastructure templates
- Managed Kubernetes services (EKS, AKS, GKE) that automatically create and modify security groups and firewall rules when deploying load balancers or NodePort services
Other platforms for T1562.007
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1AWS Security Group Ingress Rule Addition
Expected signal: CloudTrail event: AuthorizeSecurityGroupIngress with requestParameters showing port 22 and 0.0.0.0/0 CIDR. GuardDuty finding: UnauthorizedAccess:EC2/TorIPCaller if from suspicious IP.
- Test 2Azure NSG Rule Addition
Expected signal: Azure Activity Log: Microsoft.Network/networkSecurityGroups/securityRules/write operation.
- Test 3AWS GuardDuty IP Allowlisting via Pacu
Expected signal: CloudTrail event: CreateIPSet for GuardDuty. This is a critical indicator of defense impairment in AWS.
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