CVE-2015-2784
📋 TL;DR
CVE-2015-2784 is a vulnerability in the papercrop gem for Ruby on Rails where improper input validation of crop parameters allows attackers to execute arbitrary code. This affects Ruby on Rails applications using papercrop for image cropping functionality. The vulnerability is particularly dangerous because it can lead to remote code execution.
💻 Affected Systems
- papercrop gem for Ruby on Rails
📦 What is this software?
Papercrop by Papercrop Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Arbitrary code execution within the application context, potentially allowing lateral movement or data exfiltration.
If Mitigated
Limited impact if proper input validation and sandboxing are implemented at the application layer.
🎯 Exploit Status
The vulnerability involves improper input handling, making exploitation relatively straightforward for attackers familiar with Rails applications.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.3.0 and later
Vendor Advisory: https://github.com/rsantamaria/papercrop/blob/master/CHANGELOG.md
Restart Required: Yes
Instructions:
1. Update Gemfile to specify gem 'papercrop', '>= 0.3.0'
2. Run 'bundle update papercrop'
3. Restart the Rails application server
🔧 Temporary Workarounds
Input validation wrapper
allImplement custom input validation for crop parameters before passing to papercrop
# In your controller, add validation for crop_x, crop_y, crop_w, crop_h parameters
# Ensure they are numeric and within expected bounds
🧯 If You Can't Patch
- Implement strict input validation at the application level for all crop-related parameters
- Disable or remove papercrop functionality until patching is possible
🔍 How to Verify
Check if Vulnerable:
Check Gemfile.lock for papercrop version: grep -i papercrop Gemfile.lockCheck Version:
bundle show papercrop | grep -o '[0-9]\+\.[0-9]\+\.[0-9]\+'Verify Fix Applied:
Verify papercrop version is 0.3.0 or higher: bundle show papercrop📡 Detection & Monitoring
Log Indicators:
- Unusual crop parameter values in request logs
- Multiple failed crop operations with malformed input
Network Indicators:
- HTTP requests with suspicious crop parameter values
SIEM Query:
source="rails.log" AND (crop_x OR crop_y OR crop_w OR crop_h) AND NOT (crop_x=\d+ AND crop_y=\d+ AND crop_w=\d+ AND crop_h=\d+)🔗 References
- https://github.com/rsantamaria/papercrop/blob/master/CHANGELOG.md
- https://github.com/rsantamaria/papercrop/commit/b4ecd95debaf0a8712bd1d34def83f41fc6b3579
- https://github.com/rsantamaria/papercrop/blob/master/CHANGELOG.md
- https://github.com/rsantamaria/papercrop/commit/b4ecd95debaf0a8712bd1d34def83f41fc6b3579
