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Apache Log4j 1.2's JMSAppender is vulnerable to deserialization of untrusted data when Log4j 1.2 is specifically configured to use JMSAppender and an attacker can modify the Log4j configuration. By supplying attacker-controlled TopicBindingName and TopicConnectionFactoryBindingName values, the vulnerable component performs JNDI lookups to attacker-controlled resources, which can lead to remote code execution in a manner similar to later Log4Shell-style JNDI exploitation. The issue is not present in default Log4j 1.2 deployments unless JMSAppender is explicitly enabled. Log4j 1.2 is end-of-life and no longer maintained.
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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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13 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Vulnerability referenced by HPE as affecting HPE Telco Universal SLA Management <=4.6; specific technical details not provided in the bulletin excerpt.
A medium-severity vulnerability affecting Log4j version 1.x, mentioned in the vulnerability timeline.
Log4j 1.2 JMSAppender-related vulnerability (non-default configuration) enabling exploitation when JMSAppender is enabled; Log4j 1.2 is end-of-life.
Log4j 1.2 vulnerability in JMSAppender (non-default configuration) that can enable JNDI-based exploitation when JMSAppender is enabled; Log4j 1.2 is EOL.
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Every observed campaign linking this CVE to a named adversary.
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Cross-references every affected SKU, including bundled OEM variants.
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