AWSCloudTrail - Changes to Amazon VPC settings

Status: available
Severity: low
Time window: 1d
Group by: AWSRegion, AccountName, AccountUPNSuffix, AdditionalEventData, EventName, EventSource, EventTypeName, RecipientAccountId, ResponseElements, SessionMfaAuthenticated, SourceIpAddress, UserAgent, UserIdentityAccountId, UserIdentityPrincipalid, UserIdentityUserName
Source: github.com/Azure/Azure-Sentinel

Identifies changes to Amazon VPC(Virtual Private Cloud) settings that can alter network exposure, routing, or access controls. This rule identifies changes to Amazon VPC (Virtual Private Cloud) settings such as new ACL entries, routes, routetable or Gateways. AWS VPC API Docs: https://docs.aws.amazon.com/AWSEC2/latest/APIReference/OperationList-query-vpc.html'

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1078` Valid Accounts
Stealth	`T1078` Valid Accounts, `T1562.007` Impair Defenses: Disable or Modify Cloud Firewall

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

ASL AWS Network Access Control List Created with All Open Ports (Splunk)
AWS Network Access Control List Created with All Open Ports (Splunk)
AWSCloudTrail - Network ACL with all the open ports to a specified CIDR (Kusto)
EC2 Network ACL Modified (Panther)
EC2 Network Gateway Modified (Panther)
EC2 Route Table Modified (Panther)

Rule body kusto

id: 65360bb0-8986-4ade-a89d-af3cf44d28aa
name: AWSCloudTrail - Changes to Amazon VPC settings
description: |
  Identifies changes to Amazon VPC(Virtual Private Cloud) settings that can alter network exposure, routing, or access controls.
  This rule identifies changes to Amazon VPC (Virtual Private Cloud) settings such as new ACL entries, routes, routetable or Gateways. 
  AWS VPC API Docs: https://docs.aws.amazon.com/AWSEC2/latest/APIReference/OperationList-query-vpc.html'
severity: Low
status: Available
requiredDataConnectors:
 - connectorId: AWS
   dataTypes:
    - AWSCloudTrail
 - connectorId: AWSS3
   dataTypes:
    - AWSCloudTrail
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - PrivilegeEscalation
  - DefenseEvasion
relevantTechniques:
  - T1078
  - T1562.007
query: |
  let EventNameList = dynamic(["CreateNetworkAclEntry","CreateRoute","CreateRouteTable","CreateInternetGateway","CreateNatGateway"]);
  AWSCloudTrail
  | where EventName in~ (EventNameList)
  | where EventSource != "apigateway.amazonaws.com"
  | 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 StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated) by EventName, EventTypeName, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, UserIdentityPrincipalid, UserAgent,
  UserIdentityUserName, SessionMfaAuthenticated, SourceIpAddress, AWSRegion, EventSource, AdditionalEventData, ResponseElements
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
      - identifier: CloudAppAccountId
        columnName: RecipientAccountId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIpAddress
customDetails:
  AWSRegion: AWSRegion
  RecipientAccountId: RecipientAccountId
  EventName: EventName
  EventSource: EventSource
alertDetailsOverride:
  alertDisplayNameFormat: 'AWS VPC change by {{AccountName}} in {{AWSRegion}}'
  alertDescriptionFormat: 'Event {{EventName}} executed by {{AccountName}} from {{SourceIpAddress}}.'
version: 1.0.8
kind: Scheduled

Stages and Predicates

Parameters

let EventNameList = dynamic(["CreateNetworkAclEntry","CreateRoute","CreateRouteTable","CreateInternetGateway","CreateNatGateway"]);

Stage 1: `source`

AWSCloudTrail

Stage 2: `where`

| where EventName in~ (EventNameList)

Stage 3: `where`

| where EventSource != "apigateway.amazonaws.com"

Stage 4: `extend` (4 consecutive steps)

| 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]), "")

Stage 5: `summarize`

| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated) by EventName, EventTypeName, RecipientAccountId, AccountName, AccountUPNSuffix, UserIdentityAccountId, UserIdentityPrincipalid, UserAgent,
UserIdentityUserName, SessionMfaAuthenticated, SourceIpAddress, AWSRegion, EventSource, AdditionalEventData, ResponseElements

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.

Field	Kind	Values
`EventName`	in	`CreateInternetGateway` `CreateNatGateway` `CreateNetworkAclEntry` `CreateRoute` `CreateRouteTable`
`EventSource`	ne	`apigateway.amazonaws.com` transforms: `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.

Field	Source
`AWSRegion`	`summarize`
`AccountName`	`summarize`
`AccountUPNSuffix`	`summarize`
`AdditionalEventData`	`summarize`
`EndTimeUtc`	`summarize`
`EventName`	`summarize`
`EventSource`	`summarize`
`EventTypeName`	`summarize`
`RecipientAccountId`	`summarize`
`ResponseElements`	`summarize`
`SessionMfaAuthenticated`	`summarize`
`SourceIpAddress`	`summarize`
`StartTimeUtc`	`summarize`
`UserAgent`	`summarize`
`UserIdentityAccountId`	`summarize`
`UserIdentityPrincipalid`	`summarize`
`UserIdentityUserName`	`summarize`

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`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

AWSCloudTrail - Changes to Amazon VPC settings

MITRE ATT&CK coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend` (4 consecutive steps)

Stage 5: `summarize`

Indicators

Output fields

Keyboard shortcuts

Search operators

AWSCloudTrail - Changes to Amazon VPC settings

MITRE ATT&CK coverage

Rules detecting the same action

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend (4 consecutive steps)

Stage 5: summarize

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend` (4 consecutive steps)

Stage 5: `summarize`