CVE-2021-41773 PoC — Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49

Source

https://github.com/Ask-os/CVE-2021-41773

Associated Vulnerability

Title:Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49 (CVE-2021-41773)
Description:A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. 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 is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found to be incomplete, see CVE-2021-42013.

Readme


# Apache 2.4.49 Path Traversal + Remote Code Execution (CVE-2021-41773)

## Descripción de la vulnerabilidad

Esta vulnerabilidad afecta a versiones de **Apache HTTP Server 2.4.49**. Un error en la validación del path permite a atacantes remotos realizar un **Path Traversal** utilizando secuencias como `.%2e/` para acceder a rutas fuera del directorio raíz configurado.

Cuando el módulo `mod_cgi` está habilitado, un atacante puede **ejecutar comandos arbitrarios** enviando peticiones especialmente diseñadas a un archivo CGI. Esto permite **ejecución remota de código (RCE)**.

- **CVE:** [CVE-2021-41773](https://nvd.nist.gov/vuln/detail/CVE-2021-41773)
- **Severidad:** Alta
- **Vector de ataque:** Remoto, sin autenticación
- **Requisitos:** `mod_cgi` habilitado

---

## Uso del exploit

Este script permite explotar la vulnerabilidad enviando comandos remotos al servidor afectado.

### Dependencias
- Python 3
- `curl` instalado

### Ejecución

```
python3 exploit.py -i <IP_DEL_SERVIDOR> -c <COMANDO>
```

### Ejemplos

```
python3 exploit.py -i 172.17.0.2 -c "id"
python3 exploit.py -i 172.17.0.2 -c "whoami"
python3 exploit.py -i 172.17.0.2 -c "cd ../../../ && ls -la"
```

---

File Snapshot


 [4.0K]  /data/pocs/bb01ede0648d2a34a90dece087e618a0a397c434
├── [ 750]  CVE-2021-42013.py
└── [1.2K]  README.md

0 directories, 2 files

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