Security | Threat Detection | Cyberattacks | DevSecOps | Compliance

Last Thursday, a researcher from the Alibaba Cloud Security Team dropped a zero-day remote code execution exploit on Twitter, targeting the extremely popular log4j logging framework for Java (specifically, the 2.x branch called Log4j2). The vulnerability was originally discovered and reported to Apache by the Alibaba cloud security team on November 24th. MITRE assigned CVE-2021-44228 to this vulnerability, which has since been dubbed Log4Shell by security researchers.

On Thursday, December 9, a zero-day vulnerability CVE-2021-44228 (a.k.a. Log4Shell, LogJam, and Log4j) was made public. This vulnerability impacts Apache Log4j versions 2.0-beta9 to 2.14.1, and it has the highest possible CVSS score of 10.0. As of today, it is widely regarded as one of the most dangerous and widespread vulnerabilities to date.

Thanks to Detectify Crowdsource hackers, Detectify quickly developed a security test to detect Critical vulnerability CVE-2021-44228 Apache log4j RCE. This vulnerability has set the internet alight over the past few days. Right now, exploit developers and security researchers are still understanding the potential capabilities provided by the vulnerability. Detectify received a working POC for this critical 0-day vulnerability from the Crowdsource community on Friday.

A newly published critical vulnerability in Apache’s widely popular Log4j Java library, CVE-2021-44228 (CVSS score 10) was published over the weekend, causing a lot of concern.

On Dec. 9, 2021, a remote code execution (RCE) vulnerability in Apache log4j 2 was identified, (Dubbed “Log4Shell” by researchers), affecting massive amounts of servers all over the world. As this vulnerability gains high traction worldwide, it’s important to note, that not only internet facing java applications are vulnerable, as user input can traverse to another non-internet facing machines and exploit these as well.

Updated 12/20/21 On December 9, 2021, Apache published a zero-day vulnerability (CVE-2021-44228) for Apache Log4j being referred to as “Log4Shell”. This “critical” vulnerability (CVSS score: 10) allows a remote attacker to take control of an affected system. When exploited, this vulnerability allows an attacker to run arbitrary code on the device, giving full control over to the attacker.

A critical vulnerability in the popular log4j library is currently being actively targeted on a broad global scale and possibly exploited based on advisories from multiple CERTs and vendors: CISA, Apache, etc. This Java library is integrated into many IT and DevOps tooling and workflows. On Dec 10, 2021, Apache released version 2.15.0, fixing CVE-2021-44228 (dubbed Log4Shell) an RCE with a maximum CVSSv3 score of 10.

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.