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

Source

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

Provide patched version of Log4J against CVE-2021-44228 and CVE-2021-45046 as well as a script to manually patch it yourself

Readme

# Log4J Patched Dependency for Log4Shell

This repository aims to provide a patched version of the Log4J library for legacy system that can not be updated right away.

The patch consist in a modified version of the `log4j-core.x.x.x.jar` file following the [official recommandation](https://logging.apache.org/log4j/2.x/security.html) of the Apache foundation.

The modified version does not contains the `JndiLookup.class` class anymore.

### How to use it

First, **you shouldn't trust random people on internet**.

![internet dog](./misc/internet_dog.jpg)

This repository includes a script that allows to generated patched version of the library on your computer:
 - Download original library from a trusted source ([Maven](https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core))
 - Apply the patch by removing the `JndiLookup.class` file
 - Replace the `log4j-core-x.x.x.jar` on your system by the patched one (use `find / -name log4j-core*.jar` to find it)

```bash
version=2.8.2 # replace your desired version of log4j here

wget https://repo1.maven.org/maven2/org/apache/logging/log4j/log4j-core/$version/log4j-core-$version.jar

zip -q -d log4j-core-$version.jar org/apache/logging/log4j/core/lookup/JndiLookup.class
```

If you cannot apply the patch yourself, you can directly download the patched jar from this repository:
 - [log4j-core-2.0-beta9.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.0-beta9.jar)
 - [log4j-core-2.0-rc1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.0-rc1.jar)
 - [log4j-core-2.0-rc2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.0-rc2.jar)
 - [log4j-core-2.0.2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.0.2.jar)
 - [log4j-core-2.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.0.jar)
 - [log4j-core-2.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.1.jar)
 - [log4j-core-2.2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.2.jar)
 - [log4j-core-2.3.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.3.jar)
 - [log4j-core-2.4.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.4.1.jar)
 - [log4j-core-2.4.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.4.jar)
 - [log4j-core-2.5.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.5.jar)
 - [log4j-core-2.6.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.6.1.jar)
 - [log4j-core-2.6.2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.6.2.jar)
 - [log4j-core-2.6.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.6.jar)
 - [log4j-core-2.7.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.7.jar)
 - [log4j-core-2.8.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.8.1.jar)
 - [log4j-core-2.8.2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.8.2.jar)
 - [log4j-core-2.8.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.8.jar)
 - [log4j-core-2.9.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.9.0.jar)
 - [log4j-core-2.9.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.9.1.jar)
 - [log4j-core-2.10.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.10.0.jar)
 - [log4j-core-2.11.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.11.0.jar)
 - [log4j-core-2.11.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.11.1.jar)
 - [log4j-core-2.11.2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.11.2.jar)
 - [log4j-core-2.12.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.12.0.jar)
 - [log4j-core-2.12.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.12.1.jar)
 - [log4j-core-2.12.2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.12.2.jar)
 - [log4j-core-2.13.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.13.0.jar)
 - [log4j-core-2.13.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.13.1.jar)
 - [log4j-core-2.13.2.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.13.2.jar)
 - [log4j-core-2.13.3.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.13.3.jar)
 - [log4j-core-2.14.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.14.0.jar)
 - [log4j-core-2.14.1.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.14.1.jar)
 - [log4j-core-2.15.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.15.0.jar)
 - [log4j-core-2.16.0.jar](https://github.com/Aschen/log4j-patched/raw/1.0.1/log4j/log4j-core-2.16.0.jar)

_Info: version before 2.0-beta9 are not affected since they do not contains the flawed class._

File Snapshot


 [4.0K]  /data/pocs/e27bc36a5afcb0c2a7285ff3e99a9b39668bade8
├── [ 249]  download-and-patch.sh
├── [4.0K]  log4j
│   ├── [763K]  log4j-core-2.0.1.jar
│   ├── [764K]  log4j-core-2.0.2.jar
│   ├── [664K]  log4j-core-2.0-beta9.jar
│   ├── [762K]  log4j-core-2.0.jar
│   ├── [685K]  log4j-core-2.0-rc1.jar
│   ├── [750K]  log4j-core-2.0-rc2.jar
│   ├── [1.5M]  log4j-core-2.10.0.jar
│   ├── [1.5M]  log4j-core-2.11.0.jar
│   ├── [1.5M]  log4j-core-2.11.1.jar
│   ├── [1.5M]  log4j-core-2.11.2.jar
│   ├── [1.6M]  log4j-core-2.12.0.jar
│   ├── [1.6M]  log4j-core-2.12.1.jar
│   ├── [1.6M]  log4j-core-2.12.2.jar
│   ├── [1.6M]  log4j-core-2.13.0.jar
│   ├── [1.6M]  log4j-core-2.13.1.jar
│   ├── [1.6M]  log4j-core-2.13.2.jar
│   ├── [1.6M]  log4j-core-2.13.3.jar
│   ├── [1.7M]  log4j-core-2.14.0.jar
│   ├── [1.6M]  log4j-core-2.14.1.jar
│   ├── [1.7M]  log4j-core-2.15.0.jar
│   ├── [1.7M]  log4j-core-2.16.0.jar
│   ├── [804K]  log4j-core-2.1.jar
│   ├── [806K]  log4j-core-2.2.jar
│   ├── [806K]  log4j-core-2.3.jar
│   ├── [966K]  log4j-core-2.4.1.jar
│   ├── [949K]  log4j-core-2.4.jar
│   ├── [1.1M]  log4j-core-2.5.jar
│   ├── [1.1M]  log4j-core-2.6.1.jar
│   ├── [1.1M]  log4j-core-2.6.2.jar
│   ├── [1.1M]  log4j-core-2.6.jar
│   ├── [1.2M]  log4j-core-2.7.jar
│   ├── [1.3M]  log4j-core-2.8.1.jar
│   ├── [1.3M]  log4j-core-2.8.2.jar
│   ├── [1.3M]  log4j-core-2.8.jar
│   ├── [1.5M]  log4j-core-2.9.0.jar
│   └── [1.5M]  log4j-core-2.9.1.jar
├── [4.0K]  misc
│   ├── [ 336]  download-and-patch-all.sh
│   ├── [ 32K]  internet_dog.jpg
│   ├── [ 195]  versions.txt
│   └── [ 127]  ver.txt
└── [5.0K]  README.md

2 directories, 42 files

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