CVE-2013-2512
📋 TL;DR
This vulnerability in the Ruby ftpd gem allows remote attackers to execute arbitrary operating system commands by injecting shell metacharacters in LIST or NLST FTP commands. It affects any Ruby application using the vulnerable ftpd gem version, potentially giving attackers full system control.
💻 Affected Systems
- Ruby ftpd gem
📦 What is this software?
Ftpd by Ftpd Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, lateral movement, and persistent backdoor installation.
Likely Case
Remote code execution allowing attackers to run arbitrary commands on the server, potentially accessing sensitive data or using the system as a pivot point.
If Mitigated
Limited impact if proper network segmentation, least privilege, and input validation are implemented.
🎯 Exploit Status
Exploitation is straightforward - attackers can send specially crafted FTP commands with shell metacharacters to execute arbitrary commands.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.2.2 and later
Vendor Advisory: https://rubygems.org/gems/ftpd
Restart Required: Yes
Instructions:
1. Update the ftpd gem: gem update ftpd
2. Verify version is 0.2.2 or higher: gem list ftpd
3. Restart any services using the ftpd gem
4. Test FTP functionality after update
🔧 Temporary Workarounds
Input Validation/Sanitization
allImplement custom input validation to filter shell metacharacters from FTP command arguments
# Custom validation in Ruby code to sanitize FTP command inputs
Network Access Control
linuxRestrict FTP server access to trusted IP addresses only
# Use firewall rules: iptables -A INPUT -p tcp --dport 21 -s trusted_ip -j ACCEPT
# iptables -A INPUT -p tcp --dport 21 -j DROP
🧯 If You Can't Patch
- Disable or remove the FTP service entirely if not required
- Implement network segmentation to isolate the FTP server from critical systems
🔍 How to Verify
Check if Vulnerable:
Check the installed ftpd gem version: gem list ftpd | grep ftpdCheck Version:
gem list ftpd | grep ftpdVerify Fix Applied:
Verify ftpd gem version is 0.2.2 or higher: gem list ftpd📡 Detection & Monitoring
Log Indicators:
- Unusual FTP commands containing shell metacharacters like ;, |, &, $, (, ) in LIST or NLST arguments
- Unexpected process execution from FTP service user
Network Indicators:
- FTP traffic containing shell metacharacters in command arguments
- Unusual outbound connections from FTP server
SIEM Query:
source="ftp.log" AND (command="LIST" OR command="NLST") AND args="*[;|&$()]*"