Detect Disable or Modify Cloud Firewall in CrowdStrike LogScale
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/
LogScale Detection Query
#repo=base_sensor #event_simpleName=CloudAuditEvent
| CloudProvider = /(?i)(aws|azure|gcp)/
| ActionType = /(?i)(AuthorizeSecurityGroupIngress|AuthorizeSecurityGroupEgress|RevokeSecurityGroupIngress|RevokeSecurityGroupEgress|CreateSecurityGroup|DeleteSecurityGroup|networkSecurityGroups|compute\.firewalls)/
| IsOpenToAll := if(RawEvent = /0\.0\.0\.0\/0|::\/0/, "Yes", "No")
| table([_timeutc, CloudProvider, ActorUpn, ActionType, SourceIPAddress, TargetResource, IsOpenToAll])
| sort(field=_timeutc, order=desc)CrowdStrike LogScale query for Falcon Horizon / CSPM cloud audit events detecting firewall rule modifications in AWS, Azure, and GCP environments. Identifies actors making security group and NSG changes, highlights events introducing unrestricted internet access, and surfaces the target cloud resource affected.
Data Sources
Required Tables
False Positives & Tuning
- Falcon Horizon auto-remediation policies configured to automatically roll back non-compliant security group rules may generate self-referential events that trigger this detection
- Bulk security group updates during cloud account migrations or consolidations where hundreds of rules are modified in a short timeframe by authorized migration tooling
- CI/CD pipelines integrated with CrowdStrike that provision test environments with known-permissive firewall rules that are torn down after test completion
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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