The backdoor, tracked as and assigned a CVSS score of 10.0 (Critical) , allows an unauthenticated remote attacker to gain root‑level shell access to the affected system. Its trigger is remarkably simple and well‑known: when an FTP client sends a username containing the two‑character sequence ":)" (a smiley face), the backdoor activates and binds a root shell to TCP port 6200 . From there, an attacker can connect directly to gain complete control over the server.
shell_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) shell_socket.connect((target, 6200))
VSFTPD 2.0.8 is severely outdated and lacks modern security enhancements. Upgrade to the latest stable version of VSFTPD (3.0.x+) using your distribution's package manager:
nmap -p 21 --script ftp-vsftpd-backdoor <target_IP>
VSFTPD 2.0.8, released much earlier, does not contain this built-in command execution backdoor. Instead, versions in the 2.0.x series are primarily vulnerable to: vsftpd 2.0.8 exploit github
If the version is indeed v2.0.8, look for weak configuration files (usually located at /etc/vsftpd.conf ). High-risk lines include:
(like VulnHub) or a real-world server you are testing? What OS is it running on (e.g., old Ubuntu)? VulnHub/Stapler1.md at master - GitHub
While version 2.3.4 is the most searched for "exploits on GitHub," version 2.0.8 is often referenced in the context of older Linux distributions (like those found in or VulnHub challenges). 1. Configuration Bypass: The deny_file Vulnerability
Ensure unauthenticated users cannot access or write to the server. anonymous_enable=NO local_enable=YES write_enable=YES Use code with caution. Step 2: Enforce Strict Chroot Jail Isolation Prevent local users from wandering into system directories. chroot_local_user=YES allow_writeable_chroot=NO Use code with caution. The backdoor, tracked as and assigned a CVSS score of 10
: The backdoor was caught quickly by the maintainer, Chris Evans, but it remains a legendary example of a "supply chain attack" and is a staple module in the Metasploit Framework vsftpd 2.0.8 in Context
However, there is a common misconception in the security community regarding version 2.0.8. This article clarifies the security history of vsftpd, explains the confusion around version 2.0.8, and details how to audit vsftpd configurations using tools found on GitHub. The Version Confusion: VSFTPD 2.3.4 vs. 2.0.8
: Versions prior to 3.0.x (including 2.0.8) are susceptible to parsing vulnerabilities (e.g., CVE-2015-1419
msfconsole use exploit/unix/ftp/vsftpd_234_backdoor set RHOSTS [Target_IP] exploit Use code with caution. Remediation and Mitigation shell_socket = socket
If the backdoor has already been triggered, port 6200 may be open. Scanning for this port can indicate a compromised system:
Check the exact package version running on your Linux server: vsftpd -v Use code with caution.
Python automation scripts designed to scan subnets for anonymous write access on VSFTPD instances. 2. Denial of Service (DoS) via Resource Exhaustion