CVE-2015-2780
📋 TL;DR
CVE-2015-2780 is an unrestricted file upload vulnerability in Berta CMS that allows remote attackers to upload malicious files disguised as images with executable extensions. Attackers can then execute arbitrary code by accessing the uploaded file directly. This affects all Berta CMS installations with vulnerable versions.
💻 Affected Systems
- Berta CMS
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via remote code execution, allowing attackers to take over the server, steal data, or deploy ransomware.
Likely Case
Webshell deployment leading to persistent backdoor access, data exfiltration, or website defacement.
If Mitigated
No impact if proper file upload validation and access controls are implemented.
🎯 Exploit Status
Exploit code is publicly available and requires minimal technical skill to execute.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to latest Berta CMS version
Vendor Advisory: No official vendor advisory found in provided references
Restart Required: No
Instructions:
1. Download latest Berta CMS version. 2. Backup current installation. 3. Replace vulnerable files with patched versions. 4. Verify upload functionality works with proper restrictions.
🔧 Temporary Workarounds
Restrict file upload extensions
allConfigure web server to only allow specific image file extensions and block executable extensions
# Apache: Add to .htaccess
<FilesMatch "\.(php|phtml|php3|php4|php5|pl|cgi|exe|dll|bat|cmd|sh)$">
Order Deny,Allow
Deny from all
</FilesMatch>
# Nginx: Add to server block
location ~* \.(php|phtml|php3|php4|php5|pl|cgi|exe|dll|bat|cmd|sh)$ {
deny all;
}
Move upload directory outside web root
allStore uploaded files in a directory not accessible via web requests
# Move upload directory and update CMS configuration accordingly
🧯 If You Can't Patch
- Disable file upload functionality completely in Berta CMS
- Implement web application firewall (WAF) rules to block malicious upload patterns
🔍 How to Verify
Check if Vulnerable:
Attempt to upload a file with .php extension renamed to .jpg.png and check if it's accessible via web URLCheck Version:
Check Berta CMS version in admin panel or configuration filesVerify Fix Applied:
Test that only allowed image extensions can be uploaded and executable files are rejected📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads with double extensions
- Access to uploaded files with executable extensions
- POST requests to upload endpoints with suspicious content
Network Indicators:
- HTTP requests uploading files with executable extensions
- Subsequent requests to uploaded executable files
SIEM Query:
source="web_logs" AND (uri="*upload*" AND (file_ext="php" OR file_ext="exe" OR file_ext="sh")) OR (uri="*/uploads/*" AND (file_ext="php" OR file_ext="exe" OR file_ext="sh"))