AWSCloudTrail - Changes to AWS Security Group ingress and egress settings

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Id	4f19d4e3-ec5f-4abc-9e61-819eb131758c
Rulename	AWSCloudTrail - Changes to AWS Security Group ingress and egress settings
Description	A Security Group acts as a virtual firewall for an AWS instance to control inbound and outbound traffic. This rule detects AWS CloudTrail events for changes to Security Group ingress and egress settings. Investigate to validate the legitimacy of the activity and identify potential malicious activity.
Severity	Low
Tactics	DefenseEvasion
Techniques	T1562.007
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_IngressEgressSecurityGroupChange.yaml
Version	1.0.5
Arm template	4f19d4e3-ec5f-4abc-9e61-819eb131758c.json

KQL

let EventNameList = dynamic([ "AuthorizeSecurityGroupEgress", "AuthorizeSecurityGroupIngress", "RevokeSecurityGroupEgress", "RevokeSecurityGroupIngress"]);
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, RecipientAccountId, AccountName, AccountUPNSuffix, SourceIpAddress, UserAgent, SessionMfaAuthenticated, AWSRegion,
AdditionalEventData, UserIdentityAccountId, UserIdentityPrincipalid, ResponseElements

YAML

entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  - identifier: CloudAppAccountId
    columnName: RecipientAccountId
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SourceIpAddress
tactics:
- DefenseEvasion
requiredDataConnectors:
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
- dataTypes:
  - AWSCloudTrail
  connectorId: AWSS3
alertDetailsOverride:
  alertDisplayNameFormat: AWS Security Group ingress/egress change by {{AccountName}} from {{SourceIpAddress}}
  alertDescriptionFormat: AWS Security Group ingress/egress change activity {{EventName}} was detected for {{AccountName}} from {{SourceIpAddress}}.
id: 4f19d4e3-ec5f-4abc-9e61-819eb131758c
severity: Low
status: Available
customDetails:
  UserIdentityType: UserIdentityType
  EventName: EventName
  UserIdentityUserName: UserIdentityUserName
  UserIdentityArn: UserIdentityArn
  AWSRegion: AWSRegion
  UserAgent: UserAgent
query: |
  let EventNameList = dynamic([ "AuthorizeSecurityGroupEgress", "AuthorizeSecurityGroupIngress", "RevokeSecurityGroupEgress", "RevokeSecurityGroupIngress"]);
  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, RecipientAccountId, AccountName, AccountUPNSuffix, SourceIpAddress, UserAgent, SessionMfaAuthenticated, AWSRegion,
  AdditionalEventData, UserIdentityAccountId, UserIdentityPrincipalid, ResponseElements  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon Web Services/Analytic Rules/AWS_IngressEgressSecurityGroupChange.yaml
kind: Scheduled
queryPeriod: 1d
version: 1.0.5
name: AWSCloudTrail - Changes to AWS Security Group ingress and egress settings
queryFrequency: 1d
triggerThreshold: 0
relevantTechniques:
- T1562.007
description: |
  A Security Group acts as a virtual firewall for an AWS instance to control inbound and outbound traffic. This rule detects AWS CloudTrail events for changes to Security Group ingress and egress settings.
  Investigate to validate the legitimacy of the activity and identify potential malicious activity.  
triggerOperator: gt

ARM