I built a tool that detects bad cases of the Log4j vulnerability

In plain words

Log4Shell.tools is a detection tool designed to identify instances of the Log4j vulnerability. It helps security teams and developers scan for and locate problematic configurations of Log4j in their systems. The tool addresses the critical security issue that emerged in December 2021, providing a straightforward way to assess whether systems are affected by this widespread vulnerability.

written from the facts on this page · September 2026

From the sources

Paste a log line, request header, or whole log file and instantly flag Log4Shell (CVE-2021-44228) exploitation attempts — including obfuscated JNDI payloads. log4shell.tools is a small set of defensive utilities for the Log4Shell vulnerability (CVE-2021-44228). The scanner flags JNDI exploitation attempts in your logs — even obfuscated ones — while the version checker tells you whether a given Log4j build is vulnerable and what to upgrade to. Detection only: nothing here executes payloads or contacts external hosts. Below, our guides explain how Log4Shell works, how attackers obfuscate payloads, how to detect exploitation, and how to remediate for good. These tools exist to help defenders…from log4shell.tools

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