CVE-2025-63950
📋 TL;DR
An insecure deserialization vulnerability in Twittodon's download.php script allows remote, unauthenticated attackers to inject arbitrary PHP objects via the 'obj' parameter. This can lead to denial of service attacks by causing the application to crash or consume excessive resources. All users running vulnerable versions of Twittodon are affected.
💻 Affected Systems
- Twittodon
📦 What is this software?
Twittodon by Tomaszdunia
⚠️ Risk & Real-World Impact
Worst Case
Complete application denial of service, potential remote code execution if PHP object injection chains exist, and system resource exhaustion leading to server instability.
Likely Case
Denial of service causing application crashes, service disruption, and potential data corruption in affected components.
If Mitigated
Minimal impact with proper input validation and deserialization safeguards in place, potentially only causing failed requests.
🎯 Exploit Status
Exploitation requires sending crafted base64-encoded data to the 'obj' parameter. Public proof-of-concept demonstrates denial of service.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
1. Review GitHub repository for updates
2. Apply any available patches
3. Test in development environment before production
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation for the 'obj' parameter to reject or sanitize malicious payloads before deserialization.
# Add validation in download.php
# Example: Validate base64 format and length
# $obj = $_GET['obj'];
# if (!preg_match('/^[a-zA-Z0-9\/\+]*={0,2}$/', $obj) || strlen($obj) > 1024) {
# die('Invalid input');
# }
Disable download.php Access
allRestrict or disable access to the vulnerable download.php script if not required for functionality.
# Apache: Add to .htaccess
# <Files "download.php">
# Order Deny,Allow
# Deny from all
# </Files>
# Nginx: Add to server block
# location ~ /download\.php$ {
# deny all;
# return 403;
# }
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block requests containing serialized PHP objects in the 'obj' parameter.
- Monitor and rate-limit requests to download.php to reduce attack surface and detect exploitation attempts.
🔍 How to Verify
Check if Vulnerable:
Test by sending a base64-encoded serialized PHP object to the 'obj' parameter of download.php and observing application response.Check Version:
# Check Git commit hash
# git log --oneline -1
# Or check application version in source codeVerify Fix Applied:
Verify that malicious serialized objects are rejected or sanitized, and that the application no longer crashes when receiving crafted 'obj' parameter values.📡 Detection & Monitoring
Log Indicators:
- HTTP requests to download.php with unusually long 'obj' parameter values
- Application error logs showing unserialize() failures or PHP fatal errors
- Increased error rates or application crashes
Network Indicators:
- HTTP POST/GET requests to download.php containing base64-encoded data patterns
- Unusual traffic spikes to the vulnerable endpoint
- Requests with 'obj' parameter exceeding normal length
SIEM Query:
source="web_logs" AND uri="/download.php" AND (param="obj" AND value MATCHES "[a-zA-Z0-9+/=]{100,}")