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

Source

https://github.com/uint0/cve-2021-44228-helpers

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.

Readme

# CVE-2021-44228 Helpers

Helpers, examples, and exploits for cve-2021-44228. Associated blog post: https://blog.uint0.dev/cve-2021-44228/

## Helpers

### Echo chamber

`cd echochamber`

Logs input via log4j.

**Build**: `./gradlew build`

**Run**: `./gradlew run --console=plain`

### Ldap Exfil Server

`cd ldap-listener`

Ldap server that logs requests to allow for exfiltration

**Build**: `pip install -r requirements.txt`

**Run**: `python3 listener.py <port>`


## Vulnerable applications

### Spring Hibernate

`cd spring-hibernate-ex`

A sample app using Spring and Hibernate that's vulnerable to RMI deserialization.

**Build**: `./gradlew build`

**Run**: `./gradlew bootRun`


### Class Inclusion

`cd class-inclusion-ex`

A sample app with `com.sun.jndi.ldap.object.trustURLCodebase=true` thats vulnerable to class inclusion

**Build**: `./gradlew build`

**Run**: `./gradlew run --console=plain`

## Exploits

### Exploit Class Inclusion

`cd exploit-class-inclusion`

Simple instructions on how to exploit class inclusion.

### Exploit RMI Deserialization

`cd exploit-rmi-deserialization`

Simple on how to exploit RMI Deserialization for the `spring-hibernate-ex` example.

## Troubleshooting

Everything was tested with java 11 (`sdk use java 11.0.11.j9-adpt`).

File Snapshot


 [4.0K]  /data/pocs/4866674f2ed1864ec4b9ec78b13dbcd5929e482d
├── [4.0K]  class-inclusion-ex
│   ├── [4.0K]  app
│   │   ├── [ 951]  build.gradle
│   │   └── [4.0K]  src
│   │       └── [4.0K]  main
│   │           └── [4.0K]  java
│   │               └── [4.0K]  class_inclusion_ex
│   │                   └── [ 965]  App.java
│   ├── [4.0K]  gradle
│   │   └── [4.0K]  wrapper
│   │       ├── [ 58K]  gradle-wrapper.jar
│   │       └── [ 202]  gradle-wrapper.properties
│   ├── [7.9K]  gradlew
│   ├── [2.7K]  gradlew.bat
│   └── [ 382]  settings.gradle
├── [4.0K]  echochamber
│   ├── [4.0K]  app
│   │   ├── [ 946]  build.gradle
│   │   └── [4.0K]  src
│   │       └── [4.0K]  main
│   │           └── [4.0K]  java
│   │               └── [4.0K]  echochamber
│   │                   └── [ 635]  Echo.java
│   ├── [4.0K]  gradle
│   │   └── [4.0K]  wrapper
│   │       ├── [ 58K]  gradle-wrapper.jar
│   │       └── [ 202]  gradle-wrapper.properties
│   ├── [7.9K]  gradlew
│   ├── [2.7K]  gradlew.bat
│   └── [ 375]  settings.gradle
├── [4.0K]  exploit-class-inclusion
│   └── [1001]  README.md
├── [4.0K]  exploit-rmi-deserialization
│   └── [ 936]  README.md
├── [4.0K]  ldap-listener
│   ├── [ 874]  listener.py
│   └── [ 349]  requirements.txt
├── [1.3K]  README.md
└── [4.0K]  spring-hibernate-ex
    ├── [ 806]  build.gradle
    ├── [ 269]  Dockerfile
    ├── [4.0K]  gradle
    │   └── [4.0K]  wrapper
    │       ├── [ 58K]  gradle-wrapper.jar
    │       └── [ 202]  gradle-wrapper.properties
    ├── [7.9K]  gradlew
    ├── [2.7K]  gradlew.bat
    ├── [1.2K]  HELP.md
    ├── [  34]  settings.gradle
    └── [4.0K]  src
        └── [4.0K]  main
            ├── [4.0K]  java
            │   └── [4.0K]  dev
            │       └── [4.0K]  uint0
            │           └── [4.0K]  pocs
            │               └── [4.0K]  cve202144228
            │                   ├── [ 332]  Cve202144228Application.java
            │                   └── [ 561]  IndexController.java
            └── [4.0K]  resources
                └── [   1]  application.properties

30 directories, 30 files

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