Detection rules › Kusto

AWS Security Hub - Detect EC2 Security groups allowing unrestricted high-risk ports

Status
available
Severity
high
Time window
1h
Group by
AwsAccountId, AwsRegion, AwsSecurityFindingDescription, AwsSecurityFindingId, AwsSecurityFindingTitle, ComplianceSecurityControlId, SecurityGroupARN, SecurityGroupId
Source
github.com/Azure/Azure-Sentinel

This query detects EC2 Security Groups that allow unrestricted (0.0.0.0/0 or ::/0) ingress to high-risk ports using AWS Security Hub control EC2.19 findings. Publicly exposed management, database, and service ports (e.g., RDP 3389, SSH 22, SQL 1433/3306) significantly increase the risk of brute-force attacks, exploitation, and lateral movement.

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1133 External Remote Services
DiscoveryT1046 Network Service Discovery
Lateral MovementT1021 Remote Services

Rule body kusto

id: d2b6fa0f-6a4c-4c48-8c64-5e2e1ac4e7b9
name: AWS Security Hub - Detect EC2 Security groups allowing unrestricted high-risk ports
description: |
  This query detects EC2 Security Groups that allow unrestricted (0.0.0.0/0 or ::/0) ingress to high-risk ports using AWS Security Hub control EC2.19 findings.
  Publicly exposed management, database, and service ports (e.g., RDP 3389, SSH 22, SQL 1433/3306) significantly increase the risk of brute-force attacks, exploitation, and lateral movement.
severity: High
status: Available
requiredDataConnectors:
  - connectorId: AWSSecurityHub
    dataTypes:
      - AWSSecurityHubFindings
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - LateralMovement
  - Discovery
relevantTechniques:
  - T1133
  - T1021
  - T1046
tags:
  - AWS Foundational Security Best Practices v1.0.0
  - NIST 800-53 r5
query: |
  let HighRiskPorts = dynamic([3389,20,23,110,143,3306,8080,1433,9200,9300,25,445,135,21,1434,4333,5432,5500,5601,22,3000,5000,8088,8888]);
  AWSSecurityHubFindings
  | where RecordState == "ACTIVE" and ComplianceStatus == "FAILED"
  | where tostring(AwsSecurityFindingGeneratorId) == "security-control/EC2.19"
        or tostring(ComplianceSecurityControlId) == "EC2.19"
  | mv-expand Resource = Resources
  | where tostring(Resource.Type) == "AwsEc2SecurityGroup"
  | extend SGDetails = Resource.Details.AwsEc2SecurityGroup
  | extend IpPermissions = SGDetails.IpPermissions
  | mv-expand Perm = IpPermissions
  | where toint(Perm.FromPort) in (HighRiskPorts)
  | mv-expand Range = Perm.IpRanges
  | where tostring(Range.CidrIp) in ("0.0.0.0/0", "::/0")
  | summarize TimeGenerated = max(TimeGenerated), OpenHighRiskPorts = make_set(tostring(Perm.FromPort))
      by AwsAccountId, AwsRegion, AwsSecurityFindingTitle, AwsSecurityFindingDescription,
         AwsSecurityFindingId, ComplianceSecurityControlId, SecurityGroupId = tostring(SGDetails.GroupId), SecurityGroupARN = tostring(Resource.Id)
  | extend OpenHighRiskPorts = strcat_array(OpenHighRiskPorts, ", ")
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AwsAccountId
      - identifier: CloudAppAccountId
        columnName: AwsAccountId
  - entityType: CloudApplication
    fieldMappings:
      - identifier: Name
        columnName: SecurityGroupARN
customDetails:
  ComplianceControlId: ComplianceSecurityControlId
  Region: AwsRegion
  FindingId: AwsSecurityFindingId
  SecurityGroupId: SecurityGroupId
  OpenHighRiskPorts: OpenHighRiskPorts
alertDetailsOverride:
  alertDisplayNameFormat: "EC2 Security group {{SecurityGroupId}} allows unrestricted high-risk ports"
  alertDescriptionFormat: |-
    EC2 Security group {{SecurityGroupId}} allows unrestricted (0.0.0.0/0 or ::/0) ingress to high-risk ports: {{OpenHighRiskPorts}}. Restrict or remove the offending rules.
version: 1.0.0
kind: Scheduled

Stages and Predicates

Parameters

let HighRiskPorts = dynamic([3389,20,23,110,143,3306,8080,1433,9200,9300,25,445,135,21,1434,4333,5432,5500,5601,22,3000,5000,8088,8888]);

Stage 1: source

AWSSecurityHubFindings

Stage 2: where

| where RecordState == "ACTIVE" and ComplianceStatus == "FAILED"

Stage 3: where

| where tostring(AwsSecurityFindingGeneratorId) == "security-control/EC2.19"
      or tostring(ComplianceSecurityControlId) == "EC2.19"

Stage 4: mv-expand

| mv-expand Resource = Resources

Stage 5: where

| where tostring(Resource.Type) == "AwsEc2SecurityGroup"

Stage 6: extend

| extend SGDetails = Resource.Details.AwsEc2SecurityGroup

Stage 7: extend

| extend IpPermissions = SGDetails.IpPermissions

Stage 8: mv-expand

| mv-expand Perm = IpPermissions

Stage 9: where

| where toint(Perm.FromPort) in (HighRiskPorts)

Stage 10: mv-expand

| mv-expand Range = Perm.IpRanges

Stage 11: where

| where tostring(Range.CidrIp) in ("0.0.0.0/0", "::/0")

Stage 12: summarize

| summarize TimeGenerated = max(TimeGenerated), OpenHighRiskPorts = make_set(tostring(Perm.FromPort))
    by AwsAccountId, AwsRegion, AwsSecurityFindingTitle, AwsSecurityFindingDescription,
       AwsSecurityFindingId, ComplianceSecurityControlId, SecurityGroupId = tostring(SGDetails.GroupId), SecurityGroupARN = tostring(Resource.Id)

Stage 13: extend

| extend OpenHighRiskPorts = strcat_array(OpenHighRiskPorts, ", ")

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.

FieldKindValues
AwsSecurityFindingGeneratorIdeq
  • security-control/EC2.19 transforms: tostring, cased
CidrIpin
  • 0.0.0.0/0 transforms: tostring, cased
  • ::/0 transforms: tostring, cased
ComplianceSecurityControlIdeq
  • EC2.19 transforms: tostring, cased
ComplianceStatuseq
  • FAILED transforms: cased
FromPortin
  • 110 transforms: toint, cased
  • 135 transforms: toint, cased
  • 143 transforms: toint, cased
  • 1433 transforms: toint, cased
  • 1434 transforms: toint, cased
  • 20 transforms: toint, cased
  • 21 transforms: toint, cased
  • 22 transforms: toint, cased
  • 23 transforms: toint, cased
  • 25 transforms: toint, cased
  • 3000 transforms: toint, cased
  • 3306 transforms: toint, cased
  • 3389 transforms: toint, cased
  • 4333 transforms: toint, cased
  • 445 transforms: toint, cased
  • 5000 transforms: toint, cased
  • 5432 transforms: toint, cased
  • 5500 transforms: toint, cased
  • 5601 transforms: toint, cased
  • 8080 transforms: toint, cased
  • 8088 transforms: toint, cased
  • 8888 transforms: toint, cased
  • 9200 transforms: toint, cased
  • 9300 transforms: toint, cased
RecordStateeq
  • ACTIVE transforms: cased
Typeeq
  • AwsEc2SecurityGroup transforms: tostring, cased

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
AwsAccountIdsummarize
AwsRegionsummarize
AwsSecurityFindingDescriptionsummarize
AwsSecurityFindingIdsummarize
AwsSecurityFindingTitlesummarize
ComplianceSecurityControlIdsummarize
OpenHighRiskPortsextend
SecurityGroupARNsummarize
SecurityGroupIdsummarize
TimeGeneratedsummarize