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How To: Run the Log4Shell Mitigation Script for ArcGIS Server

Summary

The Log4Shell vulnerability (CVE-2021-44228) is a critical security vulnerability in version 2 of the log4j library.  This article provides steps to mitigate the risk of exploitation.  Esri is working towards a patch, but this mitigation script can be used immediately on all versions of the ArcGIS Server versions 10.6 and above.  The script may work on versions before 10.6, but it is untested on those versions.

How This Script Works
This script implements a widely documented industry approach of modifying version 2 log4j libraries to remove the JndiLookup.class file from the “core” log4j jar file so that the vulnerability can’t be exploited. This script identifies all locations in ArcGIS Server where the class files reside and then removes those class files. The script has two implementations – one for Linux and one for Windows.  These same scripts can be used against Portal for ArcGIS and ArcGIS Data Store and so if you have downloaded the log4shellmitigation script for those products then you can re-use it for these steps.


Prerequisites:  

  • Windows - the script requires Python 3.5 or greater to be installed, Python 2.7 will not work.  Python is installed in your ArcGIS Server installation directory (commonly C:\Program Files\ArcGIS\Server) under the \framework\runtime\ArcGIS\bin\Python\envs\arcgispro-py3 directory).
  • Linux - the script requires the bash shell and the zip command to be installed.  Most likely bash is already installed, and it will be unnecessary to install it.  Depending on the Linux distribution and version being used, you may need to install the zip program using either apt-get or yum.
Note:
Esri recommends verifying that you have the correct download before running these scripts. To do so, run checksum on the downloaded zip files and verify that the hash is identical to that shown in the table below. Do not extract the script prior to running checksum. For more information about running checksum, see the following article: How To: Verify an Esri download using the checksum

If the file hash does not match with what is shown below, clear your browser cache and download the file again.
Operating systemFile nameHash
Windowslog4shellmitigation.python.zip31EC8F0543348498000B7B36E0ED17354EAAE14C3B131ACC3877B6E1918D58F3
Linuxlog4shellmitigation.linux.zipDDB01B31CF7B91270DF4410F502B17D42DC21232661400982D500E79C577897B

Procedure

Windows Workflow
The following steps work for any version of ArcGIS Server 10.6 and higher.

Preparation

  1. Login as administrator or the ArcGIS Server “run as” account.  This account must have permissions to modify files in the ArcGIS Server directory.
  2. Download the log4shellmitigation.python.zip script to the ArcGIS Server machine and unzip it. The .py script contained can be placed in any location.
  3. Start a command prompt as an administrator.
  4. Change directories (“cd”) into directory where you placed the script.
  5. Enter the following command: 
<full path to Python>\python.exe log4shellmitigation.py --list <server directory>

Here’s an example of the command:

"C:\Program Files\ArcGIS\Server\framework\runtime\ArcGIS\bin\Python\envs\arcgispro-py3\python.exe"  log4shellmitigation.py --list  "c:\Program Files\ArcGIS\Server"

This lists all the files that will be changed.  Make note of these locations in case it is necessary to revert the changes later.

Notes:
The server directory is commonly “C:\Program Files\ArcGIS\Server”
If the path to Python or the Server directory has spaces in it, please put quote marks (“) around the path.

Note that it is “dash dash list” --list.  Missing a dash or inserting a space will cause the command to fail.

This script may take a minute to run as it looks through every file in the ArcGIS Server directory.  This lists which files will be updated when you run the script in ‘delete’ mode.  Take note of these in case you need to revert the changes.

Executing the script

  1. Stop the ArcGIS Server service. The following command won’t be able to modify the files if ArcGIS Server is running.
  2. Enter the following command:
<full path to Python>\python.exe log4shellmitigation.py --delete <server directory>

Here’s an example of the command:

"C:\Program Files\ArcGIS\Server\framework\runtime\ArcGIS\bin\Python\envs\arcgispro-py3\python.exe"  log4shellmitigation.py --delete "c:\Program Files\ArcGIS\Server"

This is the command that is modifying the JAR files so that log4shell cannot be exploited.

  1. Start the ArcGIS Server service.
Troubleshooting
If there are any problems and you wish to roll back the changes, please contact Esri Technical Support for assistance.


Linux Workflow

Preparation

The following steps should work against any version of ArcGIS Server 10.6 and higher.

  1. Log into your Linux machine running ArcGIS Server with the account that installed ArcGIS Server. Do not use a different non-root account, root account or superuser.
  2. Download the log4shellmitigation.linux.zip script to the ArcGIS Server machine, and unzip it. The .sh script must be placed into the parent directory of your ArcGIS Server location.

For example, if ArcGIS Server were installed in /opt/arcgis/server, then you would need to place the script in the /opt/arcgis directory.  

Note: 
If you have multiple ArcGIS Enterprise products installed on the same machine with the same parent directory and you have already run the log4shellmitigation.sh script from that same location, it is not necessary to run again.  Running the script from a parent directory will apply it to all products that share the same parent directory.
  1. Change directory to the parent directory where you placed the log4shellmitigation.sh script.
  2. Make the script executable using this command:
chmod 500 log4shellmitigation.sh
  1. Run the script using the -l (dash el) option to identify all the files that will be changed.
./log4shellmitigation.sh -l 

This lists all the files that will be modified.  No backup of these files will be made by this script.  If you wish to back up these original files, do so now by copying them to some other location.

  1. Stop ArcGIS Server. You can use any means you normally use but running the stopserver.sh script in the <Server Installation Location>/arcgis/server directory will work across most versions of Linux distributions.
  2. Run the script with no arguments:
./log4shellmitigation.sh
  1. When prompted, confirm that you wish to proceed with patching the files by entering ‘y’.
  2. Start the ArcGIS Server service. You can use any means you normally use, but running the startserver.sh script in the <Server Installation Location>/arcgis/server directory will work across most versions of Linux distributions.

Troubleshooting
If there are any problems and you wish to roll back the changes, please contact Esri Technical Support for assistance.

Related Information

Last Published: 12/28/2021

Article ID: 000026951

Software: ArcGIS Server 10.9.1, 10.9, 10.8.1, 10.8, 10.7.1, 10.7, 10.6.1, 10.6