GCP K8S Pod Create Or Modify Host Path Volume Mount

Status: Deprecated
Severity: high
Group by: protoPayload.authenticationInfo.principalEmail
Log types: GCP.AuditLog
Tags: Deprecated
Reference: https://kubernetes.io/docs/concepts/security/pod-security-standards/#host-namespaces
Source: github.com/panther-labs/panther-analysis

This detection monitors for pod creation with a hostPath volume mount. The attachment to a node's volume can allow for privilege escalation through underlying vulnerabilities or it can open up possibilities for data exfiltration or unauthorized file access. It is very rare to see this being a pod requirement. System service accounts in the kube-system namespace are excluded to prevent false positives from legitimate system components.

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1611` Escape to Host
Exfiltration	`T1041` Exfiltration Over C2 Channel

Rules detecting the same action

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

GCP Break-glass Container Workload Deployed (Sigma)
GCP K8s Pod Attached To Node Host Network (Panther)
GCP K8s Pod Using Host PID Namespace (Panther)

Rule body yaml

AnalysisType: rule
RuleID: "GCP.K8S.Pod.Create.Or.Modify.Host.Path.Volume.Mount"
DisplayName: "GCP K8S Pod Create Or Modify Host Path Volume Mount"
Enabled: false
Status: Deprecated
LogTypes:
  - GCP.AuditLog
Severity: High
Tags:
  - Deprecated
Description: >
  This detection monitors for pod creation with a hostPath volume mount. The attachment to a node's volume can allow
  for privilege escalation through underlying vulnerabilities or it can open up possibilities for data exfiltration
  or unauthorized file access. It is very rare to see this being a pod requirement. System service accounts in the
  kube-system namespace are excluded to prevent false positives from legitimate system components.
Runbook: |
  Investigate the reason of adding hostPath volume mount. Advise that it is discouraged practice.
  Create ticket if appropriate.
Reference: https://kubernetes.io/docs/concepts/security/pod-security-standards/#host-namespaces
Reports:
  MITRE ATT&CK:
    - TA0010:T1041 # Exfiltration Over C2 Channel 
    - TA0004:T1611 # Escape to Host 
Filename: gcp_k8s_pod_create_or_modify_host_path_vol_mount.py
DedupPeriodMinutes: 360
Tests:
  - Name: Pod With Suspicious Volume Mount Created
    ExpectedResult: true
    Log:
      {
        "logName": "projects/some-project/logs/cloudaudit.googleapis.com%2Factivity",
        "protoPayload":
          {
            "at_sign_type": "type.googleapis.com/google.cloud.audit.AuditLog",
            "authenticationInfo": { "principalEmail": "some.user@company.com" },
            "authorizationInfo":
              [
                {
                  "granted": true,
                  "permission": "io.k8s.core.v1.pods.create",
                  "resource": "core/v1/namespaces/default/pods/test",
                },
              ],
            "methodName": "io.k8s.core.v1.pods.create",
            "request":
              {
                "@type": "core.k8s.io/v1.Pod",
                "apiVersion": "v1",
                "kind": "Pod",
                "metadata": { "name": "test", "namespace": "default" },
                "spec":
                  {
                    "containers":
                      [
                        {
                          "image": "nginx",
                          "imagePullPolicy": "Always",
                          "name": "test",
                          "volumeMounts":
                            [{ "mountPath": "/test", "name": "test-volume" }],
                        },
                      ],
                    "volumes":
                      [
                        {
                          "hostPath":
                            {
                              "path": "/var/lib/kubelet",
                              "type": "DirectoryOrCreate",
                            },
                          "name": "test-volume",
                        },
                      ],
                  },
              },
            "requestMetadata":
              {
                "callerIP": "1.2.3.4",
                "callerSuppliedUserAgent": "kubectl/v1.28.2 (darwin/amd64) kubernetes/89a4ea3",
              },
            "resourceName": "core/v1/namespaces/default/pods/test",
            "response":
              {
                "spec":
                  {
                    "containers":
                      [
                        {
                          "image": "nginx",
                          "imagePullPolicy": "Always",
                          "name": "test",
                          "volumeMounts":
                            [{ "mountPath": "/test", "name": "test-volume" }],
                        },
                      ],
                    "volumes":
                      [
                        {
                          "hostPath":
                            {
                              "path": "/var/lib/kubelet",
                              "type": "DirectoryOrCreate",
                            },
                          "name": "test-volume",
                        },
                      ],
                  },
                "status": { "phase": "Pending", "qosClass": "BestEffort" },
              },
          },
        "receiveTimestamp": "2024-02-16 11:48:43.531373988",
        "resource":
          {
            "labels":
              {
                "cluster_name": "some-project-cluster",
                "location": "us-west1",
                "project_id": "some-project",
              },
            "type": "k8s_cluster",
          },
        "timestamp": "2024-02-16 11:48:22.742154000",
      }
  - Name: Pod With Non-Suspicious Volume Mount Created
    ExpectedResult: false
    Log:
      {
        "logName": "projects/some-project/logs/cloudaudit.googleapis.com%2Factivity",
        "protoPayload":
          {
            "at_sign_type": "type.googleapis.com/google.cloud.audit.AuditLog",
            "authenticationInfo": { "principalEmail": "some.user@company.com" },
            "authorizationInfo":
              [
                {
                  "granted": true,
                  "permission": "io.k8s.core.v1.pods.create",
                  "resource": "core/v1/namespaces/default/pods/test",
                },
              ],
            "methodName": "io.k8s.core.v1.pods.create",
            "request":
              {
                "@type": "core.k8s.io/v1.Pod",
                "apiVersion": "v1",
                "kind": "Pod",
                "metadata": { "name": "test", "namespace": "default" },
                "spec":
                  {
                    "containers":
                      [
                        {
                          "image": "nginx",
                          "imagePullPolicy": "Always",
                          "name": "test",
                          "volumeMounts":
                            [{ "mountPath": "/test", "name": "test-volume" }],
                        },
                      ],
                    "volumes":
                      [
                        {
                          "hostPath":
                            { "path": "/data", "type": "DirectoryOrCreate" },
                          "name": "test-volume",
                        },
                      ],
                  },
              },
            "requestMetadata":
              {
                "callerIP": "1.2.3.4",
                "callerSuppliedUserAgent": "kubectl/v1.28.2 (darwin/amd64) kubernetes/89a4ea3",
              },
            "resourceName": "core/v1/namespaces/default/pods/test",
            "response":
              {
                "spec":
                  {
                    "containers":
                      [
                        {
                          "image": "nginx",
                          "imagePullPolicy": "Always",
                          "name": "test",
                          "volumeMounts":
                            [{ "mountPath": "/test", "name": "test-volume" }],
                        },
                      ],
                    "volumes":
                      [
                        {
                          "hostPath":
                            { "path": "/data", "type": "DirectoryOrCreate" },
                          "name": "test-volume",
                        },
                      ],
                  },
                "status": { "phase": "Pending", "qosClass": "BestEffort" },
              },
          },
        "receiveTimestamp": "2024-02-16 11:48:43.531373988",
        "resource":
          {
            "labels":
              {
                "cluster_name": "some-project-cluster",
                "location": "us-west1",
                "project_id": "some-project",
              },
            "type": "k8s_cluster",
          },
        "timestamp": "2024-02-16 11:48:22.742154000",
      }
  - Name: Pod Not Created
    ExpectedResult: False
    Log:
      {
        "logName": "projects/some-project/logs/cloudaudit.googleapis.com%2Factivity",
        "protoPayload":
          {
            "at_sign_type": "type.googleapis.com/google.cloud.audit.AuditLog",
            "authenticationInfo": { "principalEmail": "some.user@company.com" },
            "authorizationInfo":
              [
                {
                  "granted": true,
                  "permission": "io.k8s.core.v1.pods.create",
                  "resource": "core/v1/namespaces/default/pods/test",
                },
              ],
            "methodName": "io.k8s.core.v1.pods.create",
            "request":
              {
                "@type": "core.k8s.io/v1.Pod",
                "apiVersion": "v1",
                "kind": "Pod",
                "metadata": { "name": "test", "namespace": "default" },
                "spec":
                  {
                    "containers":
                      [
                        {
                          "image": "nginx",
                          "imagePullPolicy": "Always",
                          "name": "test",
                          "volumeMounts":
                            [{ "mountPath": "/test", "name": "test-volume" }],
                        },
                      ],
                    "volumes":
                      [
                        {
                          "hostPath":
                            {
                              "path": "/var/lib/kubelet",
                              "type": "DirectoryOrCreate",
                            },
                          "name": "test-volume",
                        },
                      ],
                  },
                "status": {},
              },
            "resourceName": "core/v1/namespaces/default/pods/test",
            "response": { "status": "Failure" },
          },
        "receiveTimestamp": "2024-02-16 12:55:17.003485190",
        "resource":
          {
            "labels":
              {
                "cluster_name": "some-project-cluster",
                "location": "us-west1",
                "project_id": "some-project",
              },
            "type": "k8s_cluster",
          },
        "timestamp": "2024-02-16 12:55:00.510160000",
      }

Detection logic

Condition

not (protoPayload.response.status eq "Failure" or protoPayload.methodName not in ["io.k8s.core.v1.pods.create", "io.k8s.core.v1.pods.update", "io.k8s.core.v1.pods.patch"])
protoPayload.request.spec.volumes.hostPath.path is_not_null
protoPayload.request.spec.volumes.hostPath.path in ["/var/run/docker.sock", "/var/run/crio/crio.sock", "/var/lib/kubelet", "/var/lib/kubelet/pki", "/var/lib/docker/overlay2", "/etc/kubernetes", "/etc/kubernetes/manifests", "/etc/kubernetes/pki", "/home/admin"]
not ((protoPayload.authenticationInfo.principalEmail is_not_null and (protoPayload.authenticationInfo.principalEmail starts_with "system:kube-controller-manager" or protoPayload.authenticationInfo.principalEmail starts_with "system:kube-scheduler" or protoPayload.authenticationInfo.principalEmail starts_with "system:addon-manager" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:kube-system:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:kube-public:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:kube-node-lease:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:gke-system:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:gke-managed-system:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:gmp-system:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:gmp-public:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:config-management-system:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:istio-system:" or protoPayload.authenticationInfo.principalEmail starts_with "system:serviceaccount:asm-system:")) or protoPayload.resourceName is_not_null)
protoPayload.authorizationInfo is_not_null
protoPayload.authorizationInfo array_any

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
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:addon-manager`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:kube-controller-manager`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:kube-scheduler`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:asm-system:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:config-management-system:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:gke-managed-system:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:gke-system:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:gmp-public:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:gmp-system:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:istio-system:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:kube-node-lease:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:kube-public:`
`protoPayload.authenticationInfo.principalEmail`	starts_with	`system:serviceaccount:kube-system:`
`protoPayload.authenticationInfo.principalEmail`	is_not_null	(no value, null check)
`protoPayload.resourceName`	is_not_null	(no value, null check)
`protoPayload.methodName`	in	`io.k8s.core.v1.pods.create`, `io.k8s.core.v1.pods.patch`, `io.k8s.core.v1.pods.update`
`protoPayload.response.status`	eq	`Failure`

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
`protoPayload.authorizationInfo`	is_not_null	(no value, null check)
`protoPayload.methodName`	in	`io.k8s.core.v1.pods.create` `io.k8s.core.v1.pods.patch` `io.k8s.core.v1.pods.update`
`protoPayload.request.spec.volumes.hostPath.path`	in	`/etc/kubernetes` `/etc/kubernetes/manifests` `/etc/kubernetes/pki` `/home/admin` `/var/lib/docker/overlay2` `/var/lib/kubelet` `/var/lib/kubelet/pki` `/var/run/crio/crio.sock` `/var/run/docker.sock`
`protoPayload.request.spec.volumes.hostPath.path`	is_not_null	(no value, null check)

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
`project`	`resource.labels.project_id`
`principal`	`protoPayload.authenticationInfo.principalEmail`
`caller_ip`	`protoPayload.requestMetadata.callerIP`
`methodName`	`protoPayload.methodName`
`resourceName`	`protoPayload.resourceName`
`serviceName`	`protoPayload.serviceName`

`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)