Detect Disable or Modify Cloud Firewall in Splunk
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/
SPL Detection Query
(index=aws sourcetype=aws:cloudtrail eventName IN ("AuthorizeSecurityGroupIngress", "AuthorizeSecurityGroupEgress", "RevokeSecurityGroupIngress", "RevokeSecurityGroupEgress", "CreateSecurityGroup", "DeleteSecurityGroup"))
OR
(index=azure sourcetype="azure:audit" operationName="*networkSecurityGroups*")
OR
(index=gcp sourcetype="google:gcp:audit" methodName="*compute.firewalls*")
| eval IsOpenToAll=if(match(_raw, "0\.0\.0\.0/0|::/0"), "Yes", "No")
| eval CloudProvider=case(
sourcetype=="aws:cloudtrail", "AWS",
sourcetype=="azure:audit", "Azure",
sourcetype=="google:gcp:audit", "GCP",
true(), "Unknown")
| eval Actor=coalesce(userIdentity.arn, claims.upn, protoPayload.authenticationInfo.principalEmail)
| eval Action=coalesce(eventName, operationName, protoPayload.methodName)
| table _time, CloudProvider, Actor, Action, IsOpenToAll, sourceIPAddress, requestParameters
| sort - _timeMulti-cloud security group and firewall rule modification detection across AWS CloudTrail, Azure Audit Logs, and GCP Audit Logs. Flags rules opening access to all IPs (0.0.0.0/0). Extracts the actor identity from each cloud provider's native format.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Cloud infrastructure teams deploying new services with appropriate security group configurations
- Infrastructure-as-Code pipelines (Terraform, CloudFormation, ARM templates) that manage security groups during deployment
- Auto-scaling events that create temporary security groups for new instances
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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