Okänd säkerhetslucka öppnar för hackernätverk

Apache Log4j is a Java-based logging utility originally written by Ceki Gülcü. It is part of the Apache Logging Services, a project of the Apache Software Foundation. Log4j is one of several Java logging frameworks. Gülcü has since started the SLF4J and Logback projects, with the intention of offering a successor to Log4j. The Apache Log4j team has created a successor to Log4j 1 with version number 2. Log4j 2 was developed with a focus on the problems of Log4j 1.2, 1.3, java.util.logging and Logback, and addresses issues which appeared in those frameworks. In addition, Log4j 2 offers a plugin architecture which makes it more extensible than its predecessor. Log4j 2 is not backwards compatible with 1.x versions, although an "adapter" is available. On August 5, 2015, the Apache Logging Services Project Management Committee announced that Log4j 1 had reached end of life and that users of Log4j 1 are advised to upgrade to Apache Log4j 2.On December 9, 2021, a zero-day vulnerability involving arbitrary code execution in Log4j 2 was published by the Alibaba Cloud Security Team and given the descriptor "Log4Shell". It has been characterized by Tenable as "the single biggest, most critical vulnerability of the last decade".