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/walnutsecurity/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

cve-2021-42013.py is a python script that will help in finding Path Traversal or Remote Code Execution vulnerability in Apache 2.4.50

Readme

# Apache 2.4.50 - Path Traversal or Remote Code Execution
CVE-2021-42013.py is a python script that will help in finding Path Traversal or Remote Code Execution vulnerability in [Apache 2.4.50](https://archive.apache.org/dist/httpd/httpd-2.4.50.tar.gz). Vulnerable instance of Docker is provided to get your hands dirty on [CVE-2021-42013](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-42013)

If CGI-BIN is enabled than, we can perform Remote Code Execution but not Path Traversal, so "icons" directory has been added under Alias section in httpd.conf for checking Path Traversal vulnerability.

# Vulnerable Configurations in httpd.conf
```
1. Enable CGI-BIN
2. Add "icons" directory in Alias section
3. <Directory>Require all granted</Directory>
```

# Lab for CVE-2021-42013
### Build Docker
```
$ docker build -t cve-2021-42013 .
```
### Run Docker
```
$ docker run -it cve-2021-42013
```

# Usage cve-2021-42013.py
### Check for Path Traversal and Remote Code Execution
```
$ python3 cve-2021-42013.py -u http://172.17.0.2
```

### Path Traversal PoC
```
$ python3 cve-2021-42013.py -u http://172.17.0.2 -pt
```

### Remote Code Execution PoC
```
$ python3 cve-2021-42013.py -u http://172.17.0.2 -rce
```

### For bulk scanning, provide a text file containing IPs:
```
$ python3 cve-2021-42013.py -l list.txt
```
```
$ python3 cve-2021-42013.py -l list.txt -pt
```
```
$ python3 cve-2021-42013.py -l list.txt -rce
```

More information can be found [here](https://walnutsecurity.com/path-traversal-remote-code-execution-in-apache/).

### References
* https://nvd.nist.gov/vuln/detail/CVE-2021-42013
* https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-42013
* https://www.cve.org/CVERecord?id=CVE-2021-42013
* https://httpd.apache.org/security/vulnerabilities_24.html
* https://walnutsecurity.com/path-traversal-remote-code-execution-in-apache/

File Snapshot


 [4.0K]  /data/pocs/836f0f0391222aba0dfb4fee4c136f4e7a2bfde3
├── [5.6K]  cve-2021-42013.py
├── [ 416]  Dockerfile
├── [ 18K]  httpd.conf
└── [1.8K]  README.md

0 directories, 4 files

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