tencent cloud

All product documents
Elastic MapReduce
Notice for Apache Log4j 2 RCE Vulnerability
Last updated: 2022-05-16 12:15:40
Notice for Apache Log4j 2 RCE Vulnerability
Last updated: 2022-05-16 12:15:40

Vulnerability Description

Recently, Tencent Cloud has noticed that the remote code execution vulnerability in Apache Log4j 2 has been disclosed. There is a JNDI injection vulnerability in Log4j 2, which can be triggered when the program logs the user-input data. It can be exploited to run any code on the target server. For more information on the vulnerability, see here.

Impact

Components in EMR such as Flink, Hive, Ranger, Presto, Oozie, Knox, Storm, and Druid are affected by this vulnerability. If you are affected, fix it as instructed below.

Solution

Replace the Log4j 2 package with a safe version. Affected versions: Apache Log4j2 2.0–2.15.0-rc1. Safe versions: Apache Log4j 2.17.1.

Fix Command

1. Run the fix command in the standard EMR directory:
wget https://image-repo-gz-1259353343.cos.ap-guangzhou.myqcloud.com/user-patches/common/fix-
log4j2.sh -O fix-log4j2.sh && bash -x fix-log4j2.sh /usr/local/service
2. Fix the JAR packages in the cache directory when running the task.
Make sure that there are no problematic JAR packages in the submitted task; otherwise, they will be cached again in the task submitted next time.
Directly delete the problematic JAR packages in the directory.
/data/emr/yarn/local/filecache/ /data/emr/yarn/local/usercache/ /data1/emr/yarn/local/filecache/ /data1/emr/yarn/local/usercache/ /data2/emr/yarn/local/filecache/ /data2/emr/yarn/local/usercache/
The above lists the information of only three data disks, where the number following `/data` is the data disk index. You need to clear the corresponding files in the `/data` directory of all data disks.
3. Run the following command to fix non-standard directories (directories other than /usr/local/service).
EXTRA_DISRUPTOR_DIR=/path/to/other bash fix-log4j2.sh /path/to/other
4. Fix in other scenarios. Upgrade the six JAR packages related to the vulnerability: log4j-api, log4j-core, log4j-jul, log4j-slf4j-impl, log4j-web, and disruptor. If such a package doesn't exist, you don't need to replace it.

Service Restart and Grayscale Fix

1. Perform a fix on a node in the cluster.
Restart the Flink, Spark, Hive, Ranger, Presto, Oozie, Storm, Impala, Knox, and Druid services on the node.
Restart all resident tasks, including Flink, Storm, and Spark tasks.
2. After confirming that everything is OK by restarting the services on the node, perform the fix on other nodes.

Fix Process

1. Place the six fixed JAR packages in the fix-log4j directory of the execution directory.
2. Search for problematic packages in the target directory and replace the found ones with the six fixed JAR packages. The problematic JAR packages in the tar.gz and war packages, as well as the cache package in the /user/hadoop/share path on HDFS will be replaced at the same time.
Replace log4j-api,log4j-core,log4j-jul,log4j-slf4j-impl,log4j-web 2.0–2.17.1 with the 2.17.1 version.
Replace the versions earlier than disruptor-3.4.2.jar with the 3.4.2 version. Note that the disruptor needs to be replaced only for certain components.

Rollback Steps for Service Problems

You need to copy the problematic JAR packages back and delete the added latest JAR packages.
1. Decompress the backup file.
cd fix-log4j2
tar zxvf rm_if_no_need_to_rollback.tar.gz.1639576622
2. Copy the backup file back.
cp -r ./root/fix-log4j2/emr_fix_log4j_bak_10812_1639576622/usr/local/service/* /usr/local/service/
3. Delete the added latest Log4j JAR packages.
find /usr/local/service/ -name log4j-api-2.17.1.jar | xargs -n1 -I{} rm -f {} find /usr/local/service/ -name log4j-web-2.17.1.jar | xargs -n1 -I{} rm -f {} find /usr/local/service/ -name log4j-jul-2.17.1.jar | xargs -n1 -I{} rm -f {}
find /usr/local/service/ -name log4j-slf4j-impl-2.17.1.jar | xargs -n1 -I{} rm -f {} find /usr/local/service/ -name log4j-core-2.17.1.jar | xargs -n1 -I{} rm -f {}
4. To roll back in the /path/to/other directory, replace /usr/local/service/ with /path/to/other.

Was this page helpful?
You can also Contact Sales or Submit a Ticket for help.
Yes
No

Feedback

Contact Us

Contact our sales team or business advisors to help your business.

Technical Support

Open a ticket if you're looking for further assistance. Our Ticket is 7x24 available.

7x24 Phone Support
Hong Kong, China
+852 800 906 020 (Toll Free)
United States
+1 844 606 0804 (Toll Free)
United Kingdom
+44 808 196 4551 (Toll Free)
Canada
+1 888 605 7930 (Toll Free)
Australia
+61 1300 986 386 (Toll Free)
EdgeOne hotline
+852 300 80699
More local hotlines coming soon