Kubernetes Pod Created in System Namespace

Status: Experimental
Severity: medium
Group by: namespace, username
Log types: Amazon.EKS.Audit, Azure.MonitorActivity, GCP.AuditLog
Tags: Kubernetes, Privilege Escalation, Persistence, Defense Evasion, Unified Detection
Reference: https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/
Source: github.com/panther-labs/panther-analysis

This detection monitors for pods being created in system namespaces like kube-system, kube-public, gke-system, or kube-node-lease. These namespaces are reserved for Kubernetes control plane components and cluster infrastructure. Attackers who gain cluster access may create malicious pods in system namespaces to hide among legitimate system workloads, gain elevated privileges, or establish persistence mechanisms that are less likely to be noticed.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1525` Implant Internal Image
Privilege Escalation	`T1611` Escape to Host
Defense Impairment	`T1578.002` Modify Cloud Compute Infrastructure: Create Cloud Instance

Rule body yaml

AnalysisType: rule
RuleID: "Kubernetes.Pod.SystemNamespace"
DisplayName: "Kubernetes Pod Created in System Namespace"
Enabled: true
Status: Experimental
Filename: k8s_pod_created_in_system_namespace.py
LogTypes:
  - Amazon.EKS.Audit
  - Azure.MonitorActivity
  - GCP.AuditLog
Tags:
  - Kubernetes
  - Privilege Escalation
  - Persistence
  - Defense Evasion
  - Unified Detection
Severity: Medium
Description: >
  This detection monitors for pods being created in system namespaces like kube-system, kube-public, gke-system,
  or kube-node-lease. These namespaces are reserved for Kubernetes control plane components and cluster infrastructure.
  Attackers who gain cluster access may create malicious pods in system namespaces to hide among legitimate system
  workloads, gain elevated privileges, or establish persistence mechanisms that are less likely to be noticed.
Runbook: |
  1. Review the pod specification to identify the container images being deployed and determine if this is a legitimate system component or malicious workload
  2. Identify all API operations by the creating user in the 2 hours before and after the alert to establish intent
  3. If unauthorized, immediately delete the pod and search for other suspicious pod creations or RBAC changes across all clusters in the past 7 days
Reports:
  MITRE ATT&CK:
    - TA0004:T1611 # Privilege Escalation: Escape to Host
    - TA0003:T1525 # Persistence: Implant Internal Image
    - TA0005:T1578.002 # Defense Evasion: Modify Cloud Compute Infrastructure
Reference: https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/
DedupPeriodMinutes: 60
SummaryAttributes:
  - username
  - namespace
  - name
  - p_source_label
Tests:
  - Name: EKS pod created in kube-system
    ExpectedResult: true
    Log:
      {
        "kind": "Event",
        "apiVersion": "audit.k8s.io/v1",
        "verb": "create",
        "user": {"username": "attacker@example.com"},
        "sourceIPs": ["203.0.113.42"],
        "userAgent": "kubectl/v1.28.0",
        "objectRef": {
          "resource": "pods",
          "namespace": "kube-system",
          "name": "malicious-pod",
          "apiVersion": "v1"
        },
        "responseStatus": {"code": 201},
        "requestObject": {
          "kind": "Pod",
          "metadata": {"name": "malicious-pod", "namespace": "kube-system"},
          "spec": {
            "containers": [
              {
                "name": "backdoor",
                "image": "attacker/backdoor:latest"
              }
            ]
          }
        },
        "p_log_type": "Amazon.EKS.Audit",
        "p_source_label": "eks-cluster"
      }
  - Name: AKS pod created in kube-public
    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\":\"malicious-user@example.com\"},\"sourceIPs\":[\"1.2.3.4\"],\"objectRef\":{\"resource\":\"pods\",\"namespace\":\"kube-public\",\"name\":\"crypto-miner\"},\"responseStatus\":{\"code\":201},\"requestObject\":{\"kind\":\"Pod\",\"spec\":{\"containers\":[{\"name\":\"miner\",\"image\":\"cryptominer:latest\"}]}}}"
        },
        "p_source_label": "aks-cluster"
      }
  - Name: GKE pod created in gke-system
    ExpectedResult: true
    Log:
      {
        "protoPayload": {
          "authenticationInfo": {"principalEmail": "user@company.com"},
          "authorizationInfo": [{
            "granted": true,
            "permission": "io.k8s.core.v1.pods.create",
            "resource": "core/v1/namespaces/gke-system/pods/suspicious-pod"
          }],
          "methodName": "io.k8s.core.v1.pods.create",
          "requestMetadata": {"callerIP": "8.8.8.8"},
          "resourceName": "core/v1/namespaces/gke-system/pods/suspicious-pod",
          "serviceName": "k8s.io",
          "request": {
            "kind": "Pod",
            "metadata": {"name": "suspicious-pod"},
            "spec": {
              "containers": [{"name": "app", "image": "nginx:latest"}]
            }
          }
        },
        "resource": {
          "type": "k8s_cluster",
          "labels": {"project_id": "test-project"}
        },
        "p_log_type": "GCP.AuditLog",
        "p_source_label": "gke-cluster"
      }
  - Name: EKS pod created in kube-node-lease
    ExpectedResult: true
    Log:
      {
        "kind": "Event",
        "verb": "create",
        "user": {"username": "suspicious-user@example.com"},
        "objectRef": {
          "resource": "pods",
          "namespace": "kube-node-lease",
          "name": "hidden-pod"
        },
        "responseStatus": {"code": 201},
        "requestObject": {
          "kind": "Pod",
          "spec": {
            "containers": [{"name": "app", "image": "alpine:latest"}]
          }
        },
        "p_log_type": "Amazon.EKS.Audit",
        "p_source_label": "eks-cluster"
      }
  - Name: Pod created in application namespace
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "verb": "create",
        "user": {"username": "developer@example.com"},
        "objectRef": {
          "resource": "pods",
          "namespace": "production",
          "name": "app-pod"
        },
        "responseStatus": {"code": 201},
        "requestObject": {
          "kind": "Pod",
          "spec": {
            "containers": [{"name": "app", "image": "myapp:v1"}]
          }
        },
        "p_log_type": "Amazon.EKS.Audit"
      }
  - Name: System principal creating pod in kube-system (excluded)
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "verb": "create",
        "user": {"username": "system:serviceaccount:kube-system:controller"},
        "objectRef": {
          "resource": "pods",
          "namespace": "kube-system",
          "name": "system-pod"
        },
        "responseStatus": {"code": 201},
        "requestObject": {
          "kind": "Pod",
          "spec": {
            "containers": [{"name": "controller", "image": "k8s.gcr.io/controller:v1"}]
          }
        },
        "p_log_type": "Amazon.EKS.Audit"
      }
  - Name: Failed pod creation (excluded)
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "verb": "create",
        "user": {"username": "attacker@example.com"},
        "objectRef": {
          "resource": "pods",
          "namespace": "kube-system",
          "name": "malicious-pod"
        },
        "responseStatus": {"code": 403},
        "requestObject": {
          "kind": "Pod",
          "spec": {
            "containers": [{"name": "backdoor", "image": "attacker:latest"}]
          }
        },
        "p_log_type": "Amazon.EKS.Audit"
      }
  - Name: Deployment creating pod (not direct pod creation)
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "verb": "create",
        "user": {"username": "developer@example.com"},
        "objectRef": {
          "resource": "deployments",
          "namespace": "kube-system",
          "name": "test-deployment"
        },
        "responseStatus": {"code": 201},
        "p_log_type": "Amazon.EKS.Audit"
      }
  - Name: EKS pod eviction in kube-system (excluded)
    ExpectedResult: false
    Log:
      {
        "kind": "Event",
        "apiVersion": "audit.k8s.io/v1",
        "verb": "create",
        "user": {"username": "eks:node-manager"},
        "sourceIPs": ["34.210.208.192"],
        "userAgent": "Kubernetes Java Client/18.0.0-SNAPSHOT",
        "objectRef": {
          "resource": "pods",
          "subresource": "eviction",
          "namespace": "kube-system",
          "name": "metrics-server-86c5f959ff-rcxtk",
          "apiVersion": "v1"
        },
        "responseStatus": {
          "code": 429,
          "message": "Cannot evict pod as it would violate the pod's disruption budget.",
          "reason": "TooManyRequests"
        },
        "requestObject": {
          "apiVersion": "policy/v1",
          "kind": "Eviction",
          "metadata": {
            "name": "metrics-server-86c5f959ff-rcxtk",
            "namespace": "kube-system"
          }
        },
        "p_log_type": "Amazon.EKS.Audit",
        "p_source_label": "eks-cluster"
      }

Detection logic

Condition

not (verb ne "create" or resource ne "pods")
subresource is_null
not (responseStatus is_not_null and (responseStatus.code ge "400" or (responseStatus.code ge "1" and responseStatus.code le "16")))
not (username is_not_null and (username in ["masterclient", "aksService"] or (username starts_with "system:" and username not contains "serviceaccount")))
namespace in ["kube-system", "gke-system", "kube-node-lease", "kube-public"]

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
`username`	contains	`serviceaccount`
`username`	starts_with	`system:`
`username`	in	`aksService`, `masterclient`
`username`	is_not_null	(no value, null check)
`responseStatus.code`	ge	`1`
`responseStatus.code`	le	`16`
`responseStatus.code`	ge	`400`
`responseStatus`	is_not_null	(no value, null check)
`resource`	ne	`pods`
`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
`namespace`	in	`gke-system` `kube-node-lease` `kube-public` `kube-system`
`subresource`	is_null	(no value, null check)
`username`	contains	`serviceaccount`

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`

`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)