Apache Log4j2 - RCE (CVE-2021-44228)

CVE-2021-44228 is a critical remote code execution vulnerability in Apache Log4j2, often referred to as “Log4Shell.” It allows attackers to exploit JNDI lookups within log messages, enabling arbitrary code execution when crafted data is logged by affected systems.

CrowdSec has been tracking this vulnerability and its exploits since 10th of December 2021.

CrowdSec network data shows that most actors exploiting CVE-2021-44228 rely on broad, untargeted scans with minimal filtering. The activity is largely automated and opportunistic in nature. CrowdSec network telemetry also shows that exploitation of CVE-2021-44228 has significantly declined over the past week. Attack volumes are well below the long-term average, suggesting attackers are rapidly losing interest. The vulnerability appears to be falling out of active use across most threat landscapes.

Observed attacks typically involve injection patterns in the request path that contain variations of ${jndi:, reflecting the core technique used to trigger the remote code execution condition.