Changes to AWS Elastic Load Balancer security groups

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Id	c7bfadd4-34a6-4fa5-82f8-3691a32261e8
Rulename	Changes to AWS Elastic Load Balancer security groups
Description	Elastic Load Balancer distributes incoming traffic across multiple instances in multiple availability Zones. This increases the fault tolerance of your applications. Unwanted changes to Elastic Load Balancer specific security groups could open your environment to attack and hence needs monitoring. More information: https://medium.com/@GorillaStack/the-most-important-aws-cloudtrail-security-events-to-track-a5b9873f8255 and https://aws.amazon.com/elasticloadbalancing/.
Severity	Low
Tactics	Persistence
Techniques	T1098
Required data connectors	AWS AWSS3
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_LoadBalancerSecGroupChange.yaml
Version	1.0.3
Arm template	c7bfadd4-34a6-4fa5-82f8-3691a32261e8.json

KQL

let EventNameList = dynamic(["ApplySecurityGroupsToLoadBalancer", "SetSecurityGroups"]);
AWSCloudTrail
| where EventName in~ (EventNameList)
| extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
| extend UserName = tostring(split(UserIdentityArn, '/')[-1])
| extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
| extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
  AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
| summarize EventCount=count(), StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated)
by EventSource, EventName, UserIdentityType,  SourceIpAddress, UserAgent, SessionMfaAuthenticated, AWSRegion,
AdditionalEventData, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, UserIdentityPrincipalid, ResponseElements
| extend timestamp = StartTimeUtc

YAML

queryPeriod: 1d
query: |
  let EventNameList = dynamic(["ApplySecurityGroupsToLoadBalancer", "SetSecurityGroups"]);
  AWSCloudTrail
  | where EventName in~ (EventNameList)
  | extend UserIdentityArn = iif(isempty(UserIdentityArn), tostring(parse_json(Resources)[0].ARN), UserIdentityArn)
  | extend UserName = tostring(split(UserIdentityArn, '/')[-1])
  | extend AccountName = case( UserIdentityPrincipalid == "Anonymous", "Anonymous", isempty(UserIdentityUserName), UserName, UserIdentityUserName)
  | extend AccountName = iif(AccountName contains "@", tostring(split(AccountName, '@', 0)[0]), AccountName),
    AccountUPNSuffix = iif(AccountName contains "@", tostring(split(AccountName, '@', 1)[0]), "")
  | summarize EventCount=count(), StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated)
  by EventSource, EventName, UserIdentityType,  SourceIpAddress, UserAgent, SessionMfaAuthenticated, AWSRegion,
  AdditionalEventData, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, UserIdentityPrincipalid, ResponseElements
  | extend timestamp = StartTimeUtc  
name: Changes to AWS Elastic Load Balancer security groups
entityMappings:
- fieldMappings:
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  - columnName: RecipientAccountId
    identifier: CloudAppAccountId
  entityType: Account
- fieldMappings:
  - columnName: SourceIpAddress
    identifier: Address
  entityType: IP
queryFrequency: 1d
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_LoadBalancerSecGroupChange.yaml
requiredDataConnectors:
- connectorId: AWS
  dataTypes:
  - AWSCloudTrail
- connectorId: AWSS3
  dataTypes:
  - AWSCloudTrail
description: |
  'Elastic Load Balancer distributes incoming traffic across multiple instances in multiple availability Zones. This increases the fault tolerance of your applications.
   Unwanted changes to Elastic Load Balancer specific security groups could open your environment to attack and  hence needs monitoring.
   More information: https://medium.com/@GorillaStack/the-most-important-aws-cloudtrail-security-events-to-track-a5b9873f8255 
   and https://aws.amazon.com/elasticloadbalancing/. '  
kind: Scheduled
version: 1.0.3
status: Available
severity: Low
relevantTechniques:
- T1098
triggerOperator: gt
triggerThreshold: 0
tactics:
- Persistence
id: c7bfadd4-34a6-4fa5-82f8-3691a32261e8

ARM