Security Advisory for "Log4Shell"

Impact

A highly critical 0-day exploit (CVE-2021-44228) is found in Apache log4j 2 library on December 9, 2021.

This affects Apache log4j versions from 2.0-beta9 to 2.14.1 (inclusive).

This vulnerability allows a remote attacker to execute code on the server if the system logs an attacker-controlled string value with the attacker's JNDI LDAP server lookup.

Another vulnerability related to the same library, which was discovered on 12/14/2021 (CVE-2021-45046) and revealed another Remote Code Execution vulnerability, has been investigated by Hazelcast team as well and it is found that it does not affect Hazelcast Products under default configurations.

The finding of CVE-2021-45105 on 12/14/2021, which can cause a Denial of Service attack, was investigated by Hazelcast team and it is confirmed that it does not affect Hazelcast Products under default configurations.

The finding of CVE-2021-44832 on 12/28/2021, which is a medium vulnerability, is investigated by our security team as well, and not considered to be as critical. It requires attacker to be able to modify logging configuration, which means attacker can modify the filesystem and/or can already execute arbitrary code which is more of a general security breach rather than something log4j specific.

Note that Hazelcast IMDG and IMDG Enterprise itself is not affected.

However, given version distributions are considered to be vulnerable since related ZIP and TGZ distributions contain a vulnerable Hazelcast Management Center version.

Patches

CVE-2021-44228 is fixed in log4j 2.15.0. CVE-2021-45046 is fixed in log4j 2.16.0. CVE-2021-45105 is fixed in log4j 2.17.0. CVE-2021-44832 is fixed in log4j 2.17.1.

As of 12/21/2021, Hazelcast team has released a new version of all affected products that upgrades log4j to 2.17.0 as listed below: Hazelcast Management Center 4.2021.12-1, Hazelcast Management Center 5.0.4. Hazelcast IMDG and IMDG Enterprise 4.0.5, 4.1.8 and 4.2.4. Hazelcast Jet 4.5.3. Hazelcast Platform 5.0.2.

As of 01/06/2022, Hazelcast Management Center 4.2022.01 with the updated log4j 2.17.1 is released. log4j2.17.1 will be included in Management Center 5.1 that is expected to be released in February.

Hazelcast recommends upgrading to the latest versions available.

Workarounds

For users that an upgrade is not an option, below mitigations can be applied.

Disabling lookups via Environment Variable

Setting the environment variable LOG4J_FORMAT_MSG_NO_LOOKUPS=true . This option is the easiest to apply for containerized environments.

Disabling lookups in log4j2 configuration

Another good option since there is no need to replace JARs or no need to modify logging configuration file, users who cannot upgrade to 2.17.0 can mitigate the exposure by: