Security | Threat Detection | Cyberattacks | DevSecOps | Compliance

To understand how Elastic is currently assessing internal risk of this vulnerability in our products please see the advisory here.

Authors and Contributors: As always, security at Splunk is a family business. Credit to authors and collaborators: Ryan Kovar, Shannon Davis, Marcus LaFerrera, John Stoner, James Brodsky, Dave Herrald, Audra Streetman, Johan Bjerke, Drew Church, Mick Baccio, Lily Lee, Tamara Chacon, Ryan Becwar. If you want just to see how to find detections for the Log4j 2 RCE, skip down to the “detections” sections.

Security researchers recently disclosed the vulnerability CVE-2021-44228 in Apache’s log4j, which is a common Java-based library used for logging purposes. Popular projects, such as Struts2, Kafka, and Solr make use of log4j. The vulnerability was announced on Twitter, with a link to a github commit which shows the issue being fixed. Proof-of-concept code was also released to github which shows that the vulnerability is trivial to exploit.

Earlier today, a serious flaw was discovered in the widely used Java logging library Apache Log4j. The vulnerability, ‘Log4Shell,’ was first identified by users of a popular Minecraft forum and was apparently disclosed to the Apache Foundation by Alibaba Cloud security researchers on Nov. 24, 2021. The vulnerability has the potential to allow unauthenticated remote code execution (RCE) on nearly any machine using Log4j.

Log4j zero-day vulnerability is flooding the security updates/news everywhere. This issue has been named Log4shell and assigned CVE-2021-44228 (still awaiting analysis at the time of writing).

Apache has released version 2.16.0, which completely removes support for Message Lookups and disables JNDI by default. CrowdStrike has identified a malicious Java class file hosted on infrastructure associated with a nation-state adversary. The Java code is used to download known instances of adversary-specific tooling and is likely to be used in conjunction with the recently disclosed Log4Shell exploit (CVE-2021-44228).

On December 10th, 2021, the National Vulnerability Database (NVD) published the CVE-2021-44228 documenting a vulnerability in the Apache log4j library Java Naming and Directory Interface (JNDI) lookup feature allowing for remote code execution by an attacker who is able to manipulate log messages. A proof of concept was released on December 9th, 2021, and active scanning and exploitation attempts have increased through the time of the publishing of this brief.

The Oracle Java license change has become a hot topic amongst information technology professionals. As of January 2019, administrators who install Java 8 U 202 and later are only able to get security updates when they purchase support for each desktop. Furthermore, Java 11 and above is only available from Oracle under a commercial support agreement. The Java Oracle license change has raised concerns because support costs are expected to rise.

In a previous blog post, we took a look at Java’s custom serialization platform and what the security implications are. And more recently, I wrote about how improvements in Java 17 can help you prevent insecure deserialization. However, nowadays, people aren’t as dependent on Java’s custom serialization, opting instead to use JSON. JSON is the most widespread format for data serialization, it is human readable and not specific to Java.