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Azure NSG deleted

ID:azure_nsg_deleted_suspicious
Data type:Azure Activity
Severity:
Informational
-
Medium
MITRE ATT&CK:TA0005:T1562.007

Description​

AlphaSOC detected deletion of an Azure Network Security Group (NSG) or its security rules. NSGs provide network access controls for Azure resources. Deleting NSGs or security rules removes these network protections, potentially exposing resources to unauthorized access or enabling attacker lateral movement.

Impact​

Deleting NSGs eliminates network-level security controls, exposing Azure resources to unrestricted network access. This can allow attackers to directly access protected resources, perform lateral movement within the environment, or establish unauthorized connections. The removal of security rules may also disrupt legitimate network segmentation.

Severity​

SeverityCondition
Informational
Unexpected action, ASN, user agent or region
Low
Two unexpected properties at the same time
Medium
Three unexpected properties at the same time

Investigation and Remediation​

Review Azure Activity logs for the Microsoft.Network/networkSecurityGroups/delete or Microsoft.Network/networkSecurityGroups/securityRules/delete events. Identify which NSG or rules were deleted and the principal responsible for the action.

If unauthorized, immediately recreate the deleted NSG or rules to restore network protections. Review network logs for suspicious connections during the period when protections were absent. Rotate credentials for the compromised identity and implement Azure Policy to prevent unauthorized NSG deletions.

Known False Positives​

  • Administrators decommissioning resources and their associated NSGs
  • Infrastructure reorganization activities
  • Cleanup of unused security rules