Log4j Zero-Day RCE (CVE-2021-44228) Vulnerability
Posted by Sriram Sanka on December 11, 2021
I came to know about this Critical Vulnerability last night, and below is actual info same as the original content/Post by REDHAT https://access.redhat.com/security/cve/cve-2021-44228, Posting this as it is as I thought Its more clear in their Page on their words.
Description
A flaw was found in the Java logging library Apache Log4j 2 in versions from 2.0-beta9 and before and including 2.14.1. This could allow 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.
Statement
This issue only affects log4j versions between 2.0 and 2.14.1. In order to exploit this flaw you need:
- A remotely accessible endpoint with any protocol (HTTP, TCP, etc) that allows an attacker to send arbitrary data,
- A log statement in the endpoint that logs the attacker controlled data.
Due to the existence of JMS Appender which can use JNDI in the log4j 1.x, it is possible that log4j version 1.x is also affected by this vulnerability. The impact is still under investigation.
Mitigation
There are two possible mitigations for this flaw in versions from 2.10 to 2.14.1:
– Set the system property log4j2.formatMsgNoLookups to true, or
– Remove the JndiLookup class from the classpath. For example: zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class`
Possible Workaround :
In order to mitigate vulnerabilities, users should switch log4j2.formatMsgNoLookups to true by adding:”‐Dlog4j2.formatMsgNoLookups=True” to the JVM command for starting the application.
Latest log4j API can be downloadable from https://logging.apache.org/log4j/2.x/download.html
Source :
https://access.redhat.com/security/cve/cve-2021-44228
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