Zero-day-exploit in log4j2 which is part of elasticsearch

Is there a way to download Elasticsearch 6.8.21? The link from the download page currently gives a 404.

Does anyone have steps to reproduce any sort of log4j related issue with Elasticsearch (not logstash, etc).

What I have tried so far:

  • Change a slowlog threshhold to 1ms, so almost all queries will be printed to the slowlog
  • Send a query to Elasticsearch that includes the exploit string, something like ${}
  • Verify that the full string appears in the slowlogs

This does not result in a logged DNS query, so it seems like other methods may be required to leak data from an Elasticsearch cluster.

Update: I was using a version of Elasticsearch (7.9) that appears to not be vulnerable to any of the information leakage. Maybe someone can verify on an older version?

@dadoonet @jsvd @Christian_Dahlqvist
We are running our cluster with the given below versions. I guess we don't need to upgrade our version to 7.16.1 based on the above article. However, please confirm it

Current version details

Elasticsearch version: 7.13.x with bundled openjdk 16 2021-03-16
logstash version: 7.13 with bundled openjdk 11.0.11 2021-04-20

We are using the following repourl on our rhel machines:

Unfortunately, the latest es version seems to be Elasticsearch-oss-7.10.2-1.x86_64

Will there be any patches in near futures or is this a dead end?

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I do not understand which version is affected by the vulnerability.
Why is v7.7 affected while v7.8 is not?
Are they the same when using JDK version 11?

Does anyone understand?

I think you're misinterpreting the announcement which says:

Supported versions of Elasticsearch (6.8.9+, 7.8+) used with recent versions of the JDK (JDK9+) are not susceptible to either remote code execution or information leakage.

It doesn't say that 7.7 is affected, just that it's not a supported version (i.e. it's past EOL) so it's out of scope.

2021-12-16 edit to add: "out of scope" meaning "out of the scope of this particular sentence". There are other parts of the announcement that relate to EOL versions.


Aah! That's what I'm talking about!
I understand now.
Thank you, Mr. DavidTurner.

When will the logstash version 6.8.21 be available for download? As stated in an earlier comment, there is still a 404 error on the site of the 6.8.21 (and also the 7.16.1) version!

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Hi there,

I upgraded to 7.16.1 on my ECK cluster with the NoLookup flag in our env variables. However, I am still getting indicators from our reports that there are still files with log4j v2.11. Is there anything else we can do?

Note: the message below indicates v7.15.1 of ES but after upgrading to v7.16.1 we get something similar. Also, this filepath is also in question /usr/share/elasticsearch/lib/log4j-core-2.11.1.jar

The library `org.apache.logging.log4j:log4j-core` version `2.11.1` was detected in `Maven library manager` located at `/var/lib/kubelet/pods/<id>/volumes/` and is vulnerable to `CVE-2021-44228`, which exists in versions `< 2.15.0-rc2`.

The vulnerability was found in the [Github Security Advisory]( with vendor severity: `Critical`.

The vulnerability can be remediated by updating the library to version `2.15.0-rc2` or higher, using `mvn versions:use-latest-releases -Dincludes=org.apache.logging.log4j:log4j-core`.

Yes. It does need to be restarted. Additionally, you might need to change the ownership of jar to logtash:logstash or whatever it was before, in case it got changed while updating the jar by removing the class.

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I am also with the newest version of Elasticsearch receiving the following
/usr/share/Elasticsearch/bin/Elasticsearch-sql-cli-7.16.1.jar contains Log4J-2.x >= 2.10.0 VULNERABLE :frowning:
/usr/share/Elasticsearch/lib/Elasticsearch-log4j-7.16.1.jar contains Log4J-2.x <= 2.0-beta8 POTENTIALLY_SAFE :expressionless: (or did you already remove JndiLookup.class?)

Anyone aware of a fix for the sql-cli or does this not pertain to most users?

If you are using bash and the **/* does NOT work, then run shopt -s globstar before running the zip command.

shopt -s globstar
ls -lrt /usr/share/logstash/logstash-core/**/*/log4j-core-2.*
zip -d <output_of_above_command> org/apache/logging/log4j/core/lookup/JndiLookup.class
chown logstash:logstash <output_of_above_command>

Restart Logstash.

Can I download the latest jars of Log4j and palace it under below folders and start Elasticsearch?
Because when I did this getting error and Elasticsearch is not starting.

Probably permissions issue. That's why Elasticsearch is not starting. If you have removed class from the jar, check the permissions of the jar and make sure it is elasticsearch:elasticsearch or whatever it was before.

Getting this error, I checked all the files are having correct permissions

systemctl status Elasticsearch.service

● Elasticsearch.service - Elasticsearch
Loaded: loaded (/usr/lib/systemd/system/Elasticsearch.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Tue 2021-12-14 15:46:01 CST; 11s ago
Process: 27692 ExecStart=/usr/share/Elasticsearch/bin/systemd-entrypoint -p ${PID_DIR}/ --quiet (code=exited, status=1/FAILURE)
Main PID: 27692 (code=exited, status=1/FAILURE)

Dec 14 15:46:00 systemd-entrypoint[27692]: Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.Level
Dec 14 15:46:00 systemd-entrypoint[27692]: at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(
Dec 14 15:46:00 systemd-entrypoint[27692]: at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(
Dec 14 15:46:00 systemd-entrypoint[27692]: at java.base/java.lang.ClassLoader.loadClass(
Dec 14 15:46:00 systemd-entrypoint[27692]: ... 3 more
Dec 14 15:46:01 systemd-entrypoint[27692]: Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/logging/log4j/status/StatusListener
Dec 14 15:46:01 systemd[1]: Elasticsearch.service: main process exited, code=exited, status=1/FAILURE
Dec 14 15:46:01 systemd[1]: Failed to start Elasticsearch.
Dec 14 15:46:01 systemd[1]: Unit Elasticsearch.service entered failed state.
Dec 14 15:46:01 systemd[1]: Elasticsearch.service failed.

We are using Elasticsearch 7.14.1. With this version we have log4j-api-2.11.1.jar and log4j-core-2.11.1.jar, being shipped to customers. Apart from the above mentioned workaround and possible fixes, is it possible to simply replace log4j-api-2.11.1.jar with log4j-api-2.16.0.jar and log4j-core-2.11.1.jar with log4j-core-2.16.0.jar to completely remove the vulnerable jar file? Would you recommend that also as one fix apart from the above workarounds ? This is because customers are concerned of having some vulnerable components on their systems and are more interested in removing the problem itself(here the log4j 2.11 jar), rather than having some workaround or fixes with the vulnerable component.


Is the Elastic team aware of the new CVE-2021-45046?

Yes. They are. Their advisory does mention it at the very top.

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Is there more information on what makes Elasticsearch 5 vulnerable? We're having difficulty duplicating the vulnerability and the version of log4j in question appears (appears) to not be vulnerable: elasticsearch/apache-log4j-extras-DEPENDENCIES at 5.6 · elastic/elasticsearch · GitHub

Seems like I was looking at a cached page. Thanks.