Solr Security
The authoritative guide on implementing security is in the Solr Reference Guide. This page describes security features in general, but also provides information about CVEs that have been patched or dependencies which do not require a patch for Solr.
Also refer to the news section on the Solr Web page.
Security Announcements
If you believe you have discovered a vulnerability in Lucene or Solr, please follow these ASF guidelines for reporting it.
For each CVE listed below, please be sure to read the mailing list announcement for full details and mitigation steps.
| Date | CVE | Title | Impacted Versions | Mitigation | Links |
|---|---|---|---|---|---|
| 2020-10-12 | CVE-2020-13957 | The checks added to unauthenticated configset uploads can be circumvented | 6.6.0 to 6.6.5 7.0.0 to 7.7.3 8.0.0 to 8.6.2 | Can only be mitigated with either Solr upgrade or start argument change. | Jira issues: SOLR-14925 and SOLR-14663 |
| 2020-08-14 | CVE-2020-13941 | The Replication handler can expose information it shouldn't | < 8.6 | Upgrade to Solr 8.6, and/or ensure only trusted clients can make requests of Solr's replication handler. | |
| 2019-12-30 | CVE-2019-17558 | RCE vulnerability through VelocityResponseWriter | 5.0.0-8.3.1 | Can only be mitigated with either Solr upgrade or a configuration change. | Jira issues: SOLR-13971 and SOLR-14025 |
| 2019-11-18 | CVE-2019-12409 | RCE vulnerability due to bad config default | 8.1.1-8.2.0 | Can be mitigated with either a Solr upgrade or a configuration change. | Jira issue: SOLR-13647 - Getting issue details... STATUS |
| 2019-09-09 | CVE-2019-12401 | XML Bomb in Apache Solr versions prior to 5.0 | 1.3.0-1.4.1 3.1.0-3.6.2 4.0.0-4.10.4 | Can only be mitigated with Solr upgrade. | Jira issue: SOLR-13750 |
| 2019-07-31 | CVE-2019-0193 | Remote Code Execution via DataImportHandler | all up to 8.2.0 | Can be mitigated with either a Solr upgrade or a configuration change. | Jira issue: SOLR-13669 |
| 2019-03-06 | CVE-2019-0192 | Deserialization of untrusted data via jmx.serviceUrl | 5.0.0-5.5.5 6.0.0-6.6.5 | Can be mitigated with either a Solr upgrade or a configuration change. | Jira issue: SOLR-13301 |
| 2019-02-12 | CVE-2017-3164 | SSRF issue in Apache Solr | 1.3.0-7.6.0 | Can only be mitigated with Solr upgrade. | Jira issue: SOLR-12770 |
| 2018-04-08 | CVE-2018-1308 | XXE attack through DIH's dataConfig request parameter | 1.2-6.6.2 7.0.0-7.2.1 | Can be mitigated with either a Solr upgrade or a configuration change. | Jira issue: SOLR-11971 |
| 2017-10-26 | CVE-2016-6809 | Arbitrary Code Execution Vulnerabilty in Apache Tika | 1.2-6.6.1 7.0 | This vulnerability is with Apache Tika versions earlier than 1.14. A Tika dependency update was released in Solr 6.6.2 and Solr 7.1. Can only be mitigated with Solr upgrade. | Jira issue: SOLR-10335 |
| 2017-10-18 | CVE-2017-12629 | Several XXE & RCE vulnerabilities in Apache Solr | 5.5.0-5.5.4 6.0.0-6.6.1 7.0.0-7.0.1 | Can be mitigated with either a Solr upgrade or a configuration change. | Jira issues: SOLR-11482 and SOLR-11477 |
| 2017-09-18 | CVE-2017-9803 | Vulnerability in Kerberos delegation token functionality | 6.2.0-6.6.0 | Can only be mitigated with a Solr upgrade. | Jira issue: SOLR-11184 |
| 2017-07-07 | CVE-2017-7660 | Vulnerability in secure inter-node communication | 5.3.0-5.5.4 6.0.0-6.5.1 | Can only be mitigated with a Solr upgrade. | Jira issue: SOLR-10624 |
| 2017-02-15 | CVE-2017-3163 | ReplicationHandler path traversal attack | 1.4.0-6.4.0 | Can only be mitigated with a Solr upgrade. | Jira issue: SOLR-10031 |
Need for firewall
Even though you add SSL or Authentication plugins, it is still strongly recommended that the application server containing Solr be firewalled such the only clients with access to Solr are your own. A default/example installation of Solr allows any client with access to it to add, update, and delete documents (and of course search/read too), including access to the Solr configuration and schema files and the administrative user interface.
If there is a need to provide query access to a Solr server from the open internet, it is highly recommended to use a proxy, such as one of these.
Cross-Site Request Forgery (CSRF)
Even if a Solr instance is protected by good firewalls so that "bad guys" have no direct access, that instance may be at risk to potential "Cross-Site Request Forgery" based attacks if the following are all true:
- Some number of "good guys" have direct access to that Solr instance from their web browsers.
- A "bad guy" knows/guesses the host:port/path of the Solr instance (even though they can not access it directly)
- The bad guy can trick one of the good guy into clicking a maliciously crafted URL, or loading a webpage that contains malicious javascript.
This is because Solr's most basic behavior is to receive updates and deletes via HTTP. If you have a firewall or other security measure restricting Solr's /update handler so it only accepts connections from approved hosts/clients, but you are approved then you could inadvertently be tricked into loading a web page that initiates an HTTP Connection to Solr on your behalf.
It's important to keep this in mind when thinking about what it means to "secure" an instance of Solr (if you have not already).
A basic technique that can be used to mitigate the risk of a possible CSRF attack like this is to configure your Servlet Container so that access to paths which can modify the index (ie: /update, /update/csv, etc...) are restricted either to specific client IPs, or using HTTP Authentication.
Streaming Consideration
If streaming is enabled, you need to make sure Solr is as secure as it needs to be. When streaming is enabled, the parameters "stream.url" will go to a remote site and download the content. Likewise, "stream.file" will read a file on disk.
Streaming is disabled by default and is configured from solrconfig.xml
<requestParsers enableRemoteStreaming="false" ... />
Indirect compromise through Tika vulnerabilities
One of the contrib modules that Solr includes is called SolrCell. This module adds the Extracting Request Handler. This component utilizes Apache Tika to parse rich documents like PDF and Microsoft Office and index the document contents into Solr.
The Tika software has had some security vulnerabilities. It would be theoretically possible for an attacker to upload a specially crafted file to be processed by Tika running inside Solr, or to trick an administrator into uploading such a file, and in that way compromise the Solr install.
For reasons not related to security, it is strongly recommended that this contrib module is never used in production. Tika can crash, and if such a crash happens in the SolrCell module, Solr will crash too. If that advice is followed, it would be very difficult to utilize Tika vulnerabilities to compromise Solr.
Solr and Vulnerability Scanning Tools
Many organizations have policies where software to be installed on the network must pass an examination by a vulnerability scanner which attempts to determine if there are known vulnerabilities in the application.
Solr includes many dependencies which may trigger warnings from a vulnerability scan but which the Lucene/Solr community has determined that they are false positives. As a general rule, the Lucene PMC will not accept the output of a vulnerability scan as a security report.
The following table lists the dependencies and associated CVEs which are not considered problems for Lucene or Solr.
Solr Versions | Jar or Path | Related CVEs | Date Added | Status & Notes |
|---|---|---|---|---|
5.4.0-today |
| 2018-10237 | 31 Dec 2018 | Only used with the Carrot2 clustering engine. |
4.9.0-7.5.0 |
| 2014-0114 | 6 Jun 2018 | This is only used at compile time and it cannot be used to attack Solr. Since it is generally unnecessary, the dependency has been removed as of 7.5.0. See SOLR-12617. |
| 8.0.0-8.3.0 | commons-beanutils-1.9.3.jar | 2019-10086 | 21 Nov 2019 | While commons-beanutils was removed in 7.5, it was added back in 8.0 in error and removed again in 8.3. The vulnerable class was not used in any Solr code path. This jar remains a dependency of both Velocity and hadoop-common, but Solr does not use it in our implementations. |
4.6.0-today |
| 2012-2098, 2018-1324, 2018-11771 | 31 Dec 2018 | Only used in test framework and at build time. |
4.6.0-today |
| 3 Nov 2018 | Used only in DataImportHandler tests and example implementation, which should not be used in production. | |
4.6.0-today |
| 2018-1000632 | 31 Dec 2018 | Only used in Solr tests. |
4.6.0-today |
| 2018-10237 | 31 Dec 2018 | ?? |
6.6.1-7.6.0 |
| 6 Jun 2018 | Does not impact Solr because Solr uses Hadoop as a client library. | |
6.0.0-7.5.0 |
| 2017-14952 | 6 Jun 2018 | Issue applies only to the C++ release of ICU and not ICU4J, which is what Lucene uses. ICU4J is at v63.2 as of Lucene/Solr 7.6.0 |
4.7.0-today |
| 2017-15095, 2017-17485, 2017-7525, 2018-5968, 2018-7489, 2019-12086, 2019-12384, 2018-12814, 2019-14379, 2019-14439 2019-14540, 2019-16335 | 6 Jun 2018 | These CVEs, and most of the known jackson-databind CVEs since 2017, are all related to problematic “gadgets” that could be exploited during deserialization of untrusted data. The Jackson developers described 4 conditions that must be met in order for a problematic gadget to be exploited. See https://medium.com/@cowtowncoder/on-jackson-cves-dont-panic-here-is-what-you-need-to-know-54cd0d6e8062. Two CVEs, 14540 & 16335, are related to HikariConfig and HikariDataSource classes, neither of which are used in Solr's code base. |
| 7.7.0-8.2 | jetty-9.4.14 | 2019-10241, 2019-10247 | 18 Oct 2019 | Solr upgraded to Jetty 9.4.19 for the 8.2 release. Additionally, the path to exploit these vulnerabilities was fixed in 8.1 and 7.7.2. Earlier versions can manually patch their configurations as described in SOLR-13409. |
4.6.0-7.6.0 |
| 2018-1000056 | 31 Dec 2018 | JUnit only used in tests; CVE only refers to a Jenkins plugin not used by Solr. |
7.3.1 |
| 2014-7940, 2016-6293, 2016-7415, 2017-14952, 2017-17484, 2017-7867, 2017-7868 | 6 Jun 2018 | All of these issues apply to the C++ release of ICU and not ICU4J, which is what Lucene uses. |
| 8.2-8.3 | netty-all-4.1.29.Final.jar | 2019-16869 | 21 Nov 2019 | This is not included in Solr but is a dependency of ZooKeeper 3.5.5. The version was upgraded in ZooKeeper 3.5.6, included with Solr 8.3. The specific classes mentioned in the CVE are not used in Solr (nor in ZooKeeper as far as the Solr community can determine). |
5.2.0-today |
| 2017-14868, 2017-14949 | 31 Dec 2018 | Solr should not be exposed outside a firewall where bad actors can send HTTP requests. These two CVEs specifically involve classes (SimpleXMLProvider and XmlRepresentation, respectively) that Solr does not use in any code path. |
6.5.0-today |
| 3 Nov 2018 | Dependency for Hadoop and Calcite. ?? | |
5.4.0-7.7.2, 8.0-8.3 |
| 2018-1471 | 3 Jan 2019 | Dependency of Carrot2 and used during compilation, not at runtime (see SOLR-769). This .jar was replaced in Solr 8.3 and backported to 7.7.3 (see SOLR-13779). |
4.x-today |
| 2018-8088 | 6 Feb 2019 | The reported CVE impacts org.slf4j.ext.EventData, which is not used in Solr. |
7.3.1-7.5.0 |
| 2018-1335 | 6 Jun 2018 | Solr does not run tika-server, so this is not a problem. |
7.3.1-7.5.0 |
| 2018-1338, 2018-1339 | 6 Jun 2018 | These issues would only be exploitable if untrusted files are indexed with SolrCell. This is not recommended in production systems as indicated above. Additionally, Solr upgraded to Tika 1.18 in Solr 7.4. |
6.6.2-today |
| 3 Nov 2018 | Solr does not ship a Struts jar. This is a transitive POM listing and not included with Solr (see comment in SOLR-2849). | |
5.5.5, 6.2.0-today |
| 2016-6809, 2018-1335, 2018-1338, 2018-1339 | 6 Jun 2018 | See https://github.com/Gagravarr/VorbisJava/issues/30; reported CVEs are not related to OggVorbis at all. |
~2.9-today |
| 6 Jun 2018 | Only used in Lucene Benchmarks and Solr tests. |