​​Since December 10, in a span of just 20 days, there have been four different vulnerabilities published against Log4j. Engineers who worked long hours to update their Log4j versions to 2.15.0 on December 11th, were told three days later that they needed to do it all over again and upgrade to version 2.16.0. This is not sustainable. And yet the risks are high. Looking backward, we see that Log4j has been vulnerable since 2013 to the kinds of attacks described in CVE-2021-44228.

The high risk associated with newly discovered vulnerabilities in the highly popular Apache Log4j library – CVE-2021-44228 (also known as Log4Shell) and CVE-2021-45046 – has led to a security frenzy of unusual scale and urgency. Developers and security teams are pressed to investigate the impact of Log4j vulnerabilities on their software, revealing multiple technical challenges in the process.

Following the Dec. 9, 2021, announcement of the Log4j vulnerability, CVE 2021-44228, CrowdStrike Falcon OverWatch™ has provided customers with unrivaled protection and 24/7/365 vigilance in the face of heightened uncertainty. To OverWatch, Log4Shell is simply the latest vulnerability to exploit — a new access vector among a sea of many others.

Another — though unlikely — vulnerability was discovered in Log4j’s latest versions: CVE-2021-44832. This is an Arbitrary Code Execution exploit using, yet again, the now infamous JNDI functionality. The vulnerability lets an attacker with control over the Log4j configuration set a malicious datasource for the JDBC (Java DataBase Connectivity API) appender. The datasource refers to an attacker-controlled JNDI URI that will execute arbitrary code on the application using Log4j.

A new vulnerability was discovered in the Apache Log4j library. Tracked as CVE-2021-44832, this bug may allow arbitrary code execution in compromised systems when the attacker has permissions to modify the logging configuration file. CVE-2021-44832 has received a CVSS score of 6.6 out of 10, and it affects all versions of Log4j from 2.0-alpha7 to 2.17.0, excluding 2.3.2 and 2.12.4. This is the fourth Log4j vulnerability addressed by Apache in December 2021.

As previously predicted to unfold, at approximately 7:35 PM GMT, 28th of December 2021, another security vulnerability impacting the Log4j logging library was published as CVE-2021-44832. This new CVE-2021-44832 security vulnerability is affecting versions up to 2.17.0, which was previously thought to be fixed. This vulnerability is similar in nature to CVE-2021-4104 which affected the 1.x branch of Log4j.

The discovery of the Log4Shell vulnerability in the ubiquitous Apache Log4j package is a singular event in terms of both its impact and severity. Over 1 million attack attempts exploiting the Log4Shell vulnerability were detected within days after it was exposed, and it may take years before we see its full impact.

The Log4J library is one of the most widely-used logging libraries for Java code. On the 24th of November 2021, Alibaba’s Cloud Security Team found a vulnerability in the Log4J, also known as log4shell, framework that provides attackers with a simple way to run arbitrary code on any machine that uses a vulnerable version of the Log4J. This vulnerability was publicly disclosed on the 9th of December 2021.

The announcement of Log4j vulnerability cve-2021-44228 sent security and development teams into a tailspin and highlights the one of biggest challenges of open source security: dependency management. The open source libraries that make up up to 80% of our applications are often a tangled web of dependencies.