CVE-2018-11686
📋 TL;DR
CVE-2018-11686 is a critical remote code execution vulnerability in FlexPaper/FlowPaper's Publish Service. Attackers can execute arbitrary code on affected servers by exploiting setup.php and change_config.php files. This affects all organizations running vulnerable versions of FlexPaper/FlowPaper.
💻 Affected Systems
- FlexPaper
- FlowPaper
📦 What is this software?
Flexpaper by Flowpaper
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attackers to install malware, steal data, pivot to internal networks, or establish persistent backdoors.
Likely Case
Web server compromise leading to data theft, defacement, or cryptocurrency mining malware installation.
If Mitigated
Limited impact with proper network segmentation, web application firewalls, and restricted file permissions.
🎯 Exploit Status
Exploitation is straightforward with publicly available proof-of-concept code.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.3.7 and later
Vendor Advisory: https://flowpaper.com/blog/
Restart Required: No
Instructions:
1. Download latest version from flowpaper.com 2. Backup configuration 3. Replace files 4. Verify functionality
🔧 Temporary Workarounds
Remove vulnerable files
linuxDelete or restrict access to setup.php and change_config.php
rm /path/to/flexpaper/setup.php
rm /path/to/flexpaper/change_config.php
Web server restrictions
allBlock access to vulnerable endpoints via web server configuration
LocationMatch "^/(setup|change_config)\.php$"
Order deny,allow
Deny from all
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure
- Deploy web application firewall with RCE protection rules
🔍 How to Verify
Check if Vulnerable:
Check if setup.php and change_config.php exist in FlexPaper/FlowPaper directory and are accessible via HTTP.Check Version:
grep -r 'version' /path/to/flexpaper/ | grep -i '2\.3\.[0-6]'Verify Fix Applied:
Verify files are removed/restricted and version is 2.3.7+📡 Detection & Monitoring
Log Indicators:
- HTTP requests to setup.php or change_config.php
- Unusual POST requests with PHP code
Network Indicators:
- Traffic patterns matching exploit payloads
- Outbound connections from web server to unknown IPs
SIEM Query:
source="web_logs" AND (uri="*setup.php*" OR uri="*change_config.php*")