CVE-2017-1000037
📋 TL;DR
CVE-2017-1000037 is a critical vulnerability in RVM (Ruby Version Manager) that allows arbitrary command execution when users change directories. The vulnerability occurs because RVM automatically loads and executes files from the current working directory without proper validation. This affects all RVM users who navigate to directories containing malicious files.
💻 Affected Systems
- RVM (Ruby Version Manager)
📦 What is this software?
Rvm by Rvm Project
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root privileges if an attacker can place malicious files in a directory that a privileged user navigates to, leading to complete system takeover.
Likely Case
Arbitrary command execution as the current user when navigating to directories containing attacker-controlled files, potentially leading to data theft, lateral movement, or persistence.
If Mitigated
Limited impact with proper user privilege separation and directory access controls, though the vulnerability still exists in the software.
🎯 Exploit Status
Exploitation requires the attacker to place malicious files in a directory that the victim navigates to. Public proof-of-concept demonstrates trivial exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.29.3 and later
Vendor Advisory: https://github.com/rvm/rvm/releases/tag/1.29.3
Restart Required: No
Instructions:
1. Update RVM using: rvm get stable 2. Verify installation with: rvm --version 3. Ensure version is 1.29.3 or higher
🔧 Temporary Workarounds
Disable automatic loading
linuxDisable RVM's automatic loading of environment files from current directory
export rvm_project_rvmrc=0
export rvm_ignore_rvmrc=1
Use alternative Ruby manager
linuxTemporarily switch to rbenv or system Ruby until RVM is patched
🧯 If You Can't Patch
- Implement strict directory permissions to prevent unauthorized file creation in shared directories
- Educate users to avoid navigating to untrusted directories and to verify directory contents before changing to them
🔍 How to Verify
Check if Vulnerable:
Check RVM version with: rvm --version. If version is below 1.29.3, the system is vulnerable.Check Version:
rvm --versionVerify Fix Applied:
After updating, verify with: rvm --version | grep -q '1\.29\.3\|1\.3[0-9]\|1\.[4-9][0-9]' && echo 'Patched' || echo 'Still vulnerable'📡 Detection & Monitoring
Log Indicators:
- Unusual command execution from RVM hooks
- Suspicious file operations in .rvmrc or .versions.conf files
- Unexpected gem installations
Network Indicators:
- Unusual outbound connections following directory changes
- Downloads from unexpected sources during gem installation
SIEM Query:
process.name:rvm AND (process.args:*hook* OR process.args:*install* OR process.args:*exec*)