Because this vulnerability is over a decade old, it is widely used for educational purposes, penetration testing practice, and Capture The Flag (CTF) competitions. You can find numerous implementations of this exploit on GitHub by searching for: vsftpd-2.3.4-exploit CVE-2011-2523 Python Metasploit vsftpd_234_backdoor Standard Python Implementation Structure
ftp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) ftp_socket.connect((target_ip, 21)) ftp_socket.send(b"USER :)\r\n") ftp_socket.send(b"PASS irrelevant\r\n") ftp_socket.close()
The issue was remediated by the developers immediately upon discovery in July 2011. The primary solution is to ensure you are not running version 2.3.4. Update to a newer version of vsftpd . vsftpd 208 exploit github link
This guide breaks down the history of this vulnerability, how the exploit works, security risks when sourcing exploits from GitHub, and how to protect your systems. What is the VSFTPD 2.3.4 Backdoor?
Ensure your target virtual machine (Metasploitable) and your attacking machine (such as Kali Linux) are configured to use an isolated network, such as or an internal NAT network within VMware or VirtualBox. This prevents the vulnerable daemon from being exposed to the public internet. 3. Use Metasploit Because this vulnerability is over a decade old,
: A detailed walkthrough of the vulnerability and how to execute it. Exploitation Walkthrough
Because this vulnerability is a classic example of a backdoor, it is widely used in ethical hacking education, particularly in environments like Metasploitable. Several GitHub repositories exist to demonstrate this exploit: 1. Python Exploit Script Update to a newer version of vsftpd
In July 2011, an unknown attacker compromised the master download server for vsftpd and replaced the legitimate source code for version 2.3.4 with a backdoored version. The developer, Chris Evans, had famously designed vsftpd (which stands for "Very Secure FTP Daemon") to be impenetrable, making the irony of a supply chain hack particularly sharp. How the Backdoor Works (The "Smiley Face" Exploit)
: The official module is the vsftpd_234_backdoor from Rapid7 .