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CVE-2021-4104 is an untrusted-data deserialization vulnerability in Apache Log4j 1.2's JMSAppender component. An attacker with write access to the Log4j configuration can supply malicious TopicBindingName and TopicConnectionFactoryBindingName values, causing JMSAppender to issue JNDI requests that result in remote code execution. The vulnerability affects applications explicitly configured to use JMSAppender, which is not enabled by default. The unprotected JNDI behavior also exposes applications that reference an untrusted or attacker-accessible LDAP store, where manipulation of referenced data can enable code execution. Apache Log4j 1.2 reached end of life in August 2015.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository is a proof-of-concept (PoC) exploit for CVE-2021-4104, a remote code execution vulnerability in Apache Log4j 1.x when configured with JMSAppender and a writable log4j.properties file. The exploit demonstrates how an attacker can leverage a malicious JNDI LDAP endpoint to load a Java class (Evil.java) that executes arbitrary system commands (in this case, launching 'calc'). The repository includes Java source files for the payload (Evil.java), a test harness (Test.java), and configuration files (log4j.properties) that set up the vulnerable logging environment. The attack vector is network-based, requiring the target to connect to attacker-controlled LDAP and JMS endpoints. The PoC is operational but not weaponized, as it requires manual configuration and setup. Notable endpoints include 'tcp://localhost:61616' for JMS and 'ldap://127.0.0.1:1389/any' for JNDI. The repository structure follows a standard Java Maven web application layout, with source, resources, and webapp directories.
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A remote code execution vulnerability in Apache Log4j 1.2's JMSAppender involving deserialization of untrusted data through attacker-controlled JNDI configurations. Exploitation requires write access to the Log4j configuration and use of JMSAppender, which is not enabled by default. The plugin reports a CVSS v3 base score of 7.5 and available exploits. It recommends updating Echo's log4j packages to version 1.2.17-11 or later; the description also recommends migration to Log4j 2 because Log4j 1.2 reached end of life in August 2015.
A remote-code-execution vulnerability in Apache Log4j 1.x applications configured to use JMSAppender.
A vulnerability identified as CVE-2021-4104 affecting Unity Linux systems covered by the UTSA-2026-093019 security advisory.
Vulnerability referenced by HPE as affecting HPE Telco Universal SLA Management <=4.6; specific technical details not provided in the bulletin excerpt.
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