GCP compute.instances.create Privilege Escalation

Severity: high
Log types: GCP.AuditLog
Reference: https://rhinosecuritylabs.com/gcp/privilege-escalation-google-cloud-platform-part-1/
Source: github.com/panther-labs/panther-analysis

Detects compute.instances.create method for privilege escalation in GCP. This rule identifies when users create compute instances with service accounts that may lead to privilege escalation. Known good service accounts (GKE, Kubernetes, compute automation) are excluded to reduce false positives.

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1548` Abuse Elevation Control Mechanism

Rule body yaml

AnalysisType: rule
LogTypes:
  - GCP.AuditLog
Description: >
  Detects compute.instances.create method for privilege escalation in GCP. This rule identifies when users
  create compute instances with service accounts that may lead to privilege escalation. Known good service accounts
  (GKE, Kubernetes, compute automation) are excluded to reduce false positives.
DisplayName: "GCP compute.instances.create Privilege Escalation"
RuleID: "GCP.compute.instances.create.Privilege.Escalation"
Enabled: true
Reference: https://rhinosecuritylabs.com/gcp/privilege-escalation-google-cloud-platform-part-1/
Runbook: |
  1. Validate whether this compute instance creation with service account was authorized.
  2. Check if the service account attached has excessive privileges.
  3. Verify if the user creating the instance has a legitimate need for the service account permissions.
  4. If unauthorized, revoke the instance access and investigate for compromise.
Reports:
  MITRE ATT&CK:
    - TA0004:T1548 # Abuse Elevation Control Mechanism
Severity: High
Filename: gcp_computeinstances_create_privilege_escalation.py
DedupPeriodMinutes: 1440
Threshold: 1
Tests:
  - Name: GCP compute.instances - Potential Privilege Escalation
    ExpectedResult: true
    Log:
      {
        "protoPayload":
          {
            "at_sign_type": "type.googleapis.com/google.cloud.audit.AuditLog",
            "authenticationInfo":
              {
                "principalEmail": "some.user@company.com",
                "principalSubject": "user:some.user@company.com",
              },
            "authorizationInfo":
              [
                {
                  "granted": true,
                  "permission": "compute.instances.create",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.disks.create",
                  "resource": "projects/some-project/zones/us-central1-f/disks/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/disks/abc",
                      "service": "compute",
                      "type": "compute.disks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.subnetworks.use",
                  "resource": "projects/some-project/regions/us-central1/subnetworks/default",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/regions/us-central1/subnetworks/default",
                      "service": "compute",
                      "type": "compute.subnetworks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.subnetworks.useExternalIp",
                  "resource": "projects/some-project/regions/us-central1/subnetworks/default",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/regions/us-central1/subnetworks/default",
                      "service": "compute",
                      "type": "compute.subnetworks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.instances.setMetadata",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.instances.setServiceAccount",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
              ],
            "methodName": "v1.compute.instances.insert",
            "request":
              {
                "@type": "type.googleapis.com/compute.instances.insert",
                "disks": ...,
                "machineType": ...,
                "name": ...,
                "networkInterfaces": ...,
                "serviceAccounts":
                  [
                    {
                      "email": "abcmail@some-project.iam.gserviceaccount.com",
                      "scopes":
                        [
                          "https://www.googleapis.com/auth/cloud-platform",
                          "https://www.googleapis.com/auth/iam",
                        ],
                    },
                  ],
              },
            "requestMetadata":
              {
                "callerIP": "1.2.3.4",
                "callerSuppliedUserAgent": "(gzip),gzip(gfe)",
                "destinationAttributes": {},
                "requestAttributes":
                  { "auth": {}, "time": "2024-01-30T12:52:36.003867Z" },
              },
            "resourceLocation": ...,
            "resourceName": "projects/some-project/zones/us-central1-f/instances/abc",
            "response":
              {
                "@type": "type.googleapis.com/operation",
                "id": "8758546889396539388",
                "insertTime": "2024-01-30T04:52:35.886-08:00",
                "name": "operation-1706619154623-610293c7a6a25-934f1c35-1efebb12",
                "operationType": "insert",
                "progress": "0",
                "selfLink": "https://www.googleapis.com/compute/v1/projects/some-project/zones/us-central1-f/operations/operation-1706619154623-610293c7a6a25-934f1c35-1efebb12",
                "selfLinkWithId": "https://www.googleapis.com/compute/v1/projects/some-project/zones/us-central1-f/operations/8758546889396539388",
                "startTime": "2024-01-30T04:52:35.887-08:00",
                "status": "RUNNING",
                "targetId": "1454427709413609468",
                "targetLink": "https://www.googleapis.com/compute/v1/projects/some-project/zones/us-central1-f/instances/abc",
                "user": "some.user@company.com",
                "zone": "https://www.googleapis.com/compute/v1/projects/some-project/zones/us-central1-f",
              },
            "serviceName": "compute.googleapis.com",
          },
        "receiveTimestamp": "2024-01-30 12:52:36.642422049",
        "resource":
          {
            "labels":
              {
                "instance_id": "1454427709413609468",
                "project_id": "some-project",
                "zone": "us-central1-f",
              },
            "type": "gce_instance",
          },
        "severity": "NOTICE",
        "timestamp": "2024-01-30 12:52:34.676384000",
      }
  - Name: GCP compute.instances - Error
    ExpectedResult: false
    Log:
      {
        "protoPayload":
          {
            "at_sign_type": "type.googleapis.com/google.cloud.audit.AuditLog",
            "authenticationInfo":
              {
                "principalEmail": "some.user@company.com",
                "principalSubject": "user:some.user@company.com",
              },
            "authorizationInfo":
              [
                {
                  "granted": true,
                  "permission": "compute.instances.create",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.disks.create",
                  "resource": "projects/some-project/zones/us-central1-f/disks/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/disks/abc",
                      "service": "compute",
                      "type": "compute.disks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.subnetworks.use",
                  "resource": "projects/some-project/regions/us-central1/subnetworks/default",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/regions/us-central1/subnetworks/default",
                      "service": "compute",
                      "type": "compute.subnetworks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.subnetworks.useExternalIp",
                  "resource": "projects/some-project/regions/us-central1/subnetworks/default",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/regions/us-central1/subnetworks/default",
                      "service": "compute",
                      "type": "compute.subnetworks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.instances.setMetadata",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.instances.setServiceAccount",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
              ],
            "methodName": "v1.compute.instances.insert",
            "request":
              {
                "@type": ...,
                "disks": ...,
                "machineType": ...,
                "name": ...,
                "networkInterfaces": ...,
                "serviceAccounts":
                  [
                    {
                      "email": "abcmail@some-project.iam.gserviceaccount.com",
                      "scopes":
                        [
                          "https://www.googleapis.com/auth/cloud-platform",
                          "https://www.googleapis.com/auth/iam",
                        ],
                    },
                  ],
              },
            "requestMetadata": ...,
            "resourceLocation": ...,
            "resourceName": "projects/some-project/zones/us-central1-f/instances/abc",
            "response":
              {
                "@type": "type.googleapis.com/error",
                "error":
                  {
                    "code": 404,
                    "errors":
                      [
                        {
                          "domain": "global",
                          "message": "The resource 'abc' was not found",
                          "reason": "notFound",
                        },
                      ],
                    "message": "The resource 'abc' was not found",
                  },
              },
            "serviceName": "compute.googleapis.com",
            "status":
              { "code": 5, "message": "The resource 'abc' was not found" },
          },
        "receiveTimestamp": "2024-01-30 11:03:56.719662927",
        "resource":
          {
            "labels":
              {
                "instance_id": "",
                "project_id": "some-project",
                "zone": "us-central1-f",
              },
            "type": "gce_instance",
          },
        "severity": "ERROR",
        "timestamp": "2024-01-30 11:03:55.700872000",
      }
  - Name: GCP compute.instances - Not All Permissions
    ExpectedResult: false
    Log:
      {
        "protoPayload":
          {
            "at_sign_type": "type.googleapis.com/google.cloud.audit.AuditLog",
            "authenticationInfo":
              {
                "principalEmail": "some.user@company.com",
                "principalSubject": "user:some.user@company.com",
              },
            "authorizationInfo":
              [
                {
                  "granted": true,
                  "permission": "compute.instances.create",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.disks.create",
                  "resource": "projects/some-project/zones/us-central1-f/disks/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/disks/abc",
                      "service": "compute",
                      "type": "compute.disks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.subnetworks.use",
                  "resource": "projects/some-project/regions/us-central1/subnetworks/default",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/regions/us-central1/subnetworks/default",
                      "service": "compute",
                      "type": "compute.subnetworks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.subnetworks.useExternalIp",
                  "resource": "projects/some-project/regions/us-central1/subnetworks/default",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/regions/us-central1/subnetworks/default",
                      "service": "compute",
                      "type": "compute.subnetworks",
                    },
                },
                {
                  "granted": true,
                  "permission": "compute.instances.setMetadata",
                  "resource": "projects/some-project/zones/us-central1-f/instances/abc",
                  "resourceAttributes":
                    {
                      "name": "projects/some-project/zones/us-central1-f/instances/abc",
                      "service": "compute",
                      "type": "compute.instances",
                    },
                },
              ],
            "methodName": "v1.compute.instances.insert",
            "request": ...,
            "requestMetadata": ...,
            "resourceLocation": ...,
            "resourceName": ...,
            "response": ...,
            "serviceName": ...,
          },
        "receiveTimestamp": ...,
        "resource": ...,
      }

Detection logic

Condition

protoPayload.response.error is_null
protoPayload.methodName ends_with "compute.instances.insert"
protoPayload.authenticationInfo.principalEmail not ends_with "@cloudservices.gserviceaccount.com"

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`	ends_with	`@cloudservices.gserviceaccount.com`

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.methodName`	ends_with	`compute.instances.insert`
`protoPayload.response.error`	is_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)