# Patch log4j vulnerability on Windows
**URL:** https://discuss.elastic.co/t/patch-log4j-vulnerability-on-windows/292679
**Category:** Elasticsearch
**Created:** [December 22, 2021, 12:38pm UTC](https://discuss.elastic.co/t/patch-log4j-vulnerability-on-windows/292679 "2021-12-22T12:38:57Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Erni](https://discuss.elastic.co/u/Erni)
#### Post date: [December 22, 2021, 12:38pm UTC](https://discuss.elastic.co/t/patch-log4j-vulnerability-on-windows/292679/1 "2021-12-22T12:38:57Z")
Hi,
I was following instructions from: [Elasticsearch 5.0.0-5.6.10 and 6.0.0-6.3.2: Log4j CVE-2021-44228, CVE-2021-45046 remediation](https://discuss.elastic.co/t/elasticsearch-5-0-0-5-6-10-and-6-0-0-6-3-2-log4j-cve-2021-44228-cve-2021-45046-remediation/292054)
But changed it to powershell commands as I am runnng elasticsearch on Windows:
```auto
Copy-Item -Path "C:\elasticsearch\lib\log4j-core-2.11.1.jar" -Destination "C:\"
[System.Reflection.Assembly]::LoadWithPartialName('System.IO.Compression.FileSystem')
[System.IO.Compression.ZipFile]::ExtractToDirectory("C:\elasticsearch\lib\log4j-core-2.11.1.jar", "C:\log4j-core-2.11.1")
Remove-Item -Path "C:\log4j-core-2.11.1\org\apache\logging\log4j\core\lookup\JndiLookup.class"
[System.IO.Compression.ZipFile]::CreateFromDirectory("C:\log4j-core-2.11.1\", "C:\test\log4j-core-2.11.1.jar")
Copy-Item -Path "C:\test\log4j-core-2.11.1.jar" -Destination "C:\elasticsearch\lib\" -Force -Verbose
```
The problem is that elasticsearch is not starting after this change. I am getting following exception:
> Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/logging/log4j/core/config/properties/PropertiesConfigurationFactory
> at org.elasticsearch.cli.CommandLoggingConfigurator.configureLoggingWithoutConfig(CommandLoggingConfigurator.java:40)
> at org.elasticsearch.cli.Command.main(Command.java:87)
> at org.elasticsearch.common.settings.KeyStoreCli.main(KeyStoreCli.java:43)
> Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.core.config.properties.PropertiesConfigurationFactory
> at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:606)
> at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:168)
> at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
> ... 3 more
> Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/logging/log4j/core/config/properties/PropertiesConfigurationFactory
> at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:90)
> Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.core.config.properties.PropertiesConfigurationFactory
> at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:606)
> at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:168)
> at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
> ... 1 more
Elasticsearch version: 7.9.2
Is there a workaround for this?
---
### Author:  [@AquaX](https://discuss.elastic.co/u/AquaX)
#### Post date: [December 22, 2021, 2:15pm UTC](https://discuss.elastic.co/t/patch-log4j-vulnerability-on-windows/292679/2 "2021-12-22T14:15:09Z")
> [@Erni](#):
>
> I was following instructions from: [Elasticsearch 5.0.0-5.6.10 and 6.0.0-6.3.2: Log4j CVE-2021-44228, CVE-2021-45046 remediation](https://discuss.elastic.co/t/elasticsearch-5-0-0-5-6-10-and-6-0-0-6-3-2-log4j-cve-2021-44228-cve-2021-45046-remediation/292054)
This document is for a different version of elasticsearch that you're using.
Please read the main post about this vulnerability: [Apache Log4j2 Remote Code Execution (RCE) Vulnerability - CVE-2021-44228 - ESA-2021-31](https://discuss.elastic.co/t/apache-log4j2-remote-code-execution-rce-vulnerability-cve-2021-44228-esa-2021-31/291476)
> [@](#):
>
> The simplest remediation is to set the [JVM option](https://www.elastic.co/guide/en/elasticsearch/reference/7.16/advanced-configuration.html#set-jvm-options) -Dlog4j2.formatMsgNoLookups=true and restart each node of the cluster.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [January 19, 2022, 2:15pm UTC](https://discuss.elastic.co/t/patch-log4j-vulnerability-on-windows/292679/3 "2022-01-19T14:15:50Z")
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