Cloudanix VulnDB

CVE-2024-45217

High · 8.1

Insecure Default Initialization of Resource vulnerability in Apache Solr

CVSS

8.1

EPSS

0.7%

Published

Oct 16, 2024

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

Solr can accidentally treat certain configuration backups as fully trusted even when created without login, letting attackers run their own code on the server.

Exploitation
Remote Unauthenticated
Attacker needs
None
Complexity
Low
Impact
Remote Code Execution
Component
Application
Class
Authorization Bypass
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Restore-created ConfigSets omit the trusted metadata flag yet are implicitly treated as trusted, enabling unauthenticated requests to produce ConfigSets that can load arbitrary code via classloaders.

Why it matters to the business

Organizations running exposed Solr instances risk remote code execution and full cluster compromise without authentication controls, increasing breach likelihood and operational disruption.

How an attack unfolds

An attacker issues an unauthenticated Restore command to create a new-named ConfigSet from backup; the missing trusted flag causes implicit trust; the resulting ConfigSet is then used to load attacker-supplied classes into the Solr classloader.

How to fix it

Enable Authentication and Authorization on all Solr instances. Otherwise upgrade to 8.11.4 or 9.7.0. The listed Hibernate Validator fixes are unrelated to this Solr issue.

How to confirm the fix worked

After upgrade or auth enablement, verify that Restore-created ConfigSets contain explicit trusted metadata set only for authenticated uploads; test by attempting unauthenticated Restore and confirming the resulting ConfigSet is not treated as trusted.

Typical attack path

  1. Identify an unauthenticated Solr endpoint
  2. Issue Restore API command to create a new ConfigSet name from existing backup
  3. Confirm the created ConfigSet lacks explicit trusted=false metadata
  4. Upload and reference malicious classes via the implicitly trusted ConfigSet
  5. Trigger classloading to execute arbitrary code

How to detect it

Review Solr request logs for Restore commands lacking authentication tokens; search for newly created ConfigSets without explicit trusted metadata; inspect classloader activity for unexpected custom code loads.

What your security team should do

  • Immediately enable Solr Authentication/Authorization if not already active
  • Upgrade all instances to 8.11.4 or 9.7.0
  • Audit existing ConfigSets for unexpected trusted status
  • Monitor for unusual Restore API usage in access logs

The record

New ConfigSets that are created via a Restore command, which copy a configSet from the backup and give it a new name, are created without setting the "trusted" metadata. ConfigSets that do not contain the flag are trusted implicitly if the metadata is missing, therefore this leads to "trusted" ConfigSets that may not have been created with an Authenticated request. "trusted" ConfigSets are able to load custom code into classloaders, therefore the flag is supposed to only be set when the request that uploads the ConfigSet is Authenticated & Authorized. This issue affects Apache Solr: from 6.6.0 before 8.11.4, from 9.0.0 before 9.7.0. This issue does not affect Solr instances that are secured via Authentication/Authorization. Users are primarily recommended to use Authentication and Authorization when running Solr. However, upgrading to version 9.7.0, or 8.11.4 will mitigate this issue otherwise.

Affected packages

Ecosystem Package Introduced Fixed
Maven org.apache.solr:solr 6.6.0 8.11.4
Maven org.apache.solr:solr 9.0.0 9.7.0
Bitnami solr 6.6.0 8.11.4
Ubuntu:20.04:LTS lucene-solr 0 No fix
Ubuntu:22.04:LTS lucene-solr 0 No fix
Ubuntu:24.04:LTS lucene-solr 0 No fix
Ubuntu:24.10 lucene-solr 0 No fix
Ubuntu:25.04 lucene-solr 0 No fix
Ubuntu:25.10 lucene-solr 0 No fix
Ubuntu:Pro:14.04:LTS lucene-solr 0 No fix
Ubuntu:Pro:16.04:LTS lucene-solr 0 No fix
Ubuntu:Pro:18.04:LTS lucene-solr 0 No fix
Ubuntu:Pro:20.04:LTS lucene-solr 0 No fix
maven org.apache.solr/solr 6.6.0 8.11.4
maven org.apache.solr/solr 9.0.0 9.7.0

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