Kubernetes NodePort Service Deployed

Severity: high
Log types: Amazon.EKS.Audit, Azure.MonitorActivity, GCP.AuditLog
Tags: Kubernetes, Exploit Public-Facing Application, Initial Access, Unified Detection
Reference: https://kubernetes.io/docs/tutorials/kubernetes-basics/expose/expose-intro/
Source: github.com/panther-labs/panther-analysis

This detection monitors for any Kubernetes service deployed with type NodePort. A NodePort service allows an attacker to expose a set of pods hosting the service to the internet by opening their port and redirecting traffic here. This can be used to bypass network controls and intercept traffic, creating a direct line to the outside network.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1190` Exploit Public-Facing Application

Rule body yaml

AnalysisType: rule
RuleID: "Kubernetes.Service.NodePort.Deployed"
DisplayName: "Kubernetes NodePort Service Deployed"
Enabled: true
Filename: k8s_service_nodeport.py
LogTypes:
  - Amazon.EKS.Audit
  - Azure.MonitorActivity
  - GCP.AuditLog
Severity: High
Description: >
  This detection monitors for any Kubernetes service deployed with type NodePort. A NodePort
  service allows an attacker to expose a set of pods hosting the service to the internet by
  opening their port and redirecting traffic here. This can be used to bypass network controls
  and intercept traffic, creating a direct line to the outside network.
Runbook: |
  1. Identify all services created by the username in the 48 hours before the alert to understand deployment patterns
  2. Check the NodePort service specification to determine if it exposes cluster-critical services or standard application workloads
  3. Review exposed ports and compare against documented internal services in the past 30 days to verify if this is authorized
Reference: https://kubernetes.io/docs/tutorials/kubernetes-basics/expose/expose-intro/
Tags:
  - Kubernetes
  - Exploit Public-Facing Application
  - Initial Access
  - Unified Detection
Reports:
  MITRE ATT&CK:
    - TA0001:T1190 # Exploit Public-Facing Application
Tests:
  - Name: EKS NodePort Service Created
    ExpectedResult: true
    Log:
      {
        "kind": "Event",
        "apiVersion": "audit.k8s.io/v1",
        "verb": "create",
        "user": {"username": "user@example.com"},
        "sourceIPs": ["1.2.3.4"],
        "userAgent": "kubectl/v1.28.2",
        "objectRef": {
          "resource": "services",
          "namespace": "default",
          "name": "test-ns",
          "apiVersion": "v1"
        },
        "responseStatus": {"code": 201},
        "requestObject": {
          "kind": "Service",
          "apiVersion": "v1",
          "spec": {
            "type": "NodePort",
            "ports": [{
              "port": 5678,
              "targetPort": 8080,
              "protocol": "TCP"
            }]
          }
        },
        "p_log_type": "Amazon.EKS.Audit",
        "p_source_label": "eks-cluster"
      }
  - Name: AKS NodePort Service Created
    ExpectedResult: true
    Log:
      {
        "p_log_type": "Azure.MonitorActivity",
        "category": "kube-audit",
        "operationName": "Microsoft.ContainerService/managedClusters/diagnosticLogs/Read",
        "properties": {
          "log": "{\"kind\":\"Event\",\"apiVersion\":\"audit.k8s.io/v1\",\"verb\":\"create\",\"user\":{\"username\":\"admin@example.com\"},\"sourceIPs\":[\"10.0.0.1\"],\"objectRef\":{\"resource\":\"services\",\"namespace\":\"default\",\"name\":\"test-svc\"},\"responseStatus\":{\"code\":201},\"requestObject\":{\"kind\":\"Service\",\"spec\":{\"type\":\"NodePort\",\"ports\":[{\"port\":80}]}}}"
        },
        "p_source_label": "aks-cluster"
      }
  - Name: GCP GKE NodePort Service Created
    ExpectedResult: true
    Log:
      {
        "protoPayload": {
          "authenticationInfo": {"principalEmail": "user@company.com"},
          "authorizationInfo": [{
            "granted": true,
            "permission": "io.k8s.core.v1.services.create",
            "resource": "core/v1/namespaces/default/services/test-ns"
          }],
          "methodName": "io.k8s.core.v1.services.create",
          "request": {
            "@type": "core.k8s.io/v1.Service",
            "apiVersion": "v1",
            "kind": "Service",
            "spec": {
              "type": "NodePort",
              "ports": [{"port": 5678, "targetPort": 8080}]
            }
          },
          "requestMetadata": {"callerIP": "1.2.3.4"},
          "resourceName": "core/v1/namespaces/default/services/test-ns",
          "serviceName": "k8s.io",
          "status": {}
        },
        "resource": {
          "labels": {"project_id": "test-project"},
          "type": "k8s_cluster"
        },
        "p_log_type": "GCP.AuditLog",
        "p_source_label": "gke-cluster"
      }
  - Name: ClusterIP Service Created
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "verb": "create",
        "objectRef": {"resource": "services", "namespace": "default"},
        "responseStatus": {"code": 201},
        "requestObject": {
          "spec": {"type": "ClusterIP"}
        },
        "p_log_type": "Amazon.EKS.Audit"
      }
  - Name: Service Creation Failed
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "verb": "create",
        "objectRef": {"resource": "services", "namespace": "default"},
        "responseStatus": {"code": 409, "status": "Failure"},
        "requestObject": {
          "spec": {"type": "NodePort"}
        },
        "p_log_type": "Amazon.EKS.Audit"
      }
  - Name: Not a Service Creation
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "verb": "get",
        "objectRef": {"resource": "services", "namespace": "default"},
        "p_log_type": "Amazon.EKS.Audit"
      }

Detection logic

Condition

not (verb ne "create" or resource ne "services")
not (responseStatus is_not_null and (responseStatus.code ge "400" or (responseStatus.code ge "1" and responseStatus.code le "16")))
serviceType eq "NodePort"

This rule also runs imperative logic the parser cannot express as a filter; the conditions above are the structured part it could extract.

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`responseStatus.code`	ge	`1`
`responseStatus.code`	le	`16`
`responseStatus.code`	ge	`400`
`responseStatus`	is_not_null	(no value, null check)
`resource`	ne	`services`
`verb`	ne	`create`

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
`serviceType`	eq	`NodePort`

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
`username`
`sourceIPs`
`userAgent`
`namespace`
`verb`
`resource`
`requestURI`
`responseStatus`
`cluster`	`p_source_label`
`name`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`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)