log4j

CVE-2021-44228

Apache Log4j2 2.0-beta9 through 2.12.1 and 2.13.0 through 2.15.0 JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints.

CVE-2021-4104

Versions 1.x, which are no longer maintained, have a similar vulnerability.

summary

A zero-day remote code execution vulnerability has been discovered, allowing attackers to take complete control of systems without authentication.
The vulnerability was publicly disclosed via GitHub on 9.12.2021.

According to the current status, the vulnerability has been exploited first on 01.12.2021, but mass attacks only became known with the release on 9.12.2021.

reflection

The Log4j log output enables the inclusion of a wide field of possible variables. This cannot only be used internally from a system perspective but also from any remote location. Attackers can call external Java libraries via e.g. ${jdni:ldap:// or ${jndi:ldaps://, which opens the possibility to perform shell dropping without much additional effort. In addition, attackers can use ${jndi:rmi to execute commands directly within the current environment.
For any cloud service, the Log4j log output could be used to read credentials – such as access tokens – potentially allowing wide-ranging access to cloud services. The following guide contains ndaal‘s expert information, and measures to handle the ongoing Log4Shell cybersecurity incident and attack wave caused by a critical vulnerability in the Apache Log4j logging library v2.x.

The document will be updated frequently and is available here:

https://tknk.io/D6St