Security | Threat Detection | Cyberattacks | DevSecOps | Compliance

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.

A previously unknown zero-day vulnerability in Log4j 2.x has been reported on December 9, 2021. If your organization deploys or uses Java applications or hardware running Log4j 2.x your organization is likely affected.

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.

The Metasploit Framework is a Ruby-based, open-source framework that is used by information security professionals and cybercriminals to find, exploit, and validate system vulnerabilities. The framework consists of various exploitation tools and penetration testing tools. Information security teams most commonly use Metasploit for penetration testing (or “ethical hacking”) to identify and remediate any existing vulnerabilities across an organization’s networks.

There are almost 165,000 known CVEs (Common Vulnerabilities and Exposures) listed in the NIST Database. In October of 2020, the NSA published a list of the 25 CVEs most likely to be exploited by Nation-State attackers in China; Checkpoint software found over 3 million attempts to penetrate networks or steal files using these known vulnerabilities.