CVE-2021-36719
📋 TL;DR
CVE-2021-36719 is an unrestricted file upload vulnerability in PineApp Mail Secure's nicUpload.php file that allows authenticated attackers to upload malicious files and execute arbitrary code on the server. This affects PineApp Mail Secure installations where attackers have valid user credentials. Successful exploitation leads to complete server compromise.
💻 Affected Systems
- PineApp Mail Secure
📦 What is this software?
Mail Secure by Cybonet
⚠️ Risk & Real-World Impact
Worst Case
Complete server takeover with remote code execution, data exfiltration, lateral movement within the network, and persistent backdoor installation.
Likely Case
Attacker gains shell access to the mail server, can read/modify emails, access user credentials, and pivot to other systems in the network.
If Mitigated
With proper network segmentation and monitoring, impact limited to mail server isolation and quick detection of unauthorized file uploads.
🎯 Exploit Status
Exploitation requires authenticated access but is straightforward once credentials are obtained
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references
Vendor Advisory: https://www.gov.il/en/departments/faq/cve_advisories
Restart Required: Yes
Instructions:
1. Contact PineApp vendor for security patches 2. Apply vendor-provided patches 3. Restart PineApp Mail Secure service 4. Verify patch application
🔧 Temporary Workarounds
Remove nicUpload.php
linuxDelete or rename the vulnerable nicUpload.php file to prevent exploitation
mv /path/to/nicUpload.php /path/to/nicUpload.php.disabled
Restrict file upload permissions
linuxSet strict file permissions on upload directories and validate file types
chmod 644 /path/to/upload/directory/*
chown root:root /path/to/upload/directory
🧯 If You Can't Patch
- Implement strict network segmentation to isolate PineApp Mail Secure from critical systems
- Enable detailed logging of file upload activities and implement real-time monitoring for suspicious uploads
🔍 How to Verify
Check if Vulnerable:
Check if nicUpload.php exists in PineApp Mail Secure installation directory and review file upload functionalityCheck Version:
Check PineApp Mail Secure version through web interface or configuration filesVerify Fix Applied:
Verify nicUpload.php has been removed/patched and test file upload functionality with restricted file types📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to nicUpload.php
- Execution of unexpected files in upload directories
- Multiple failed authentication attempts followed by successful upload
Network Indicators:
- Unexpected outbound connections from mail server
- Traffic to suspicious IPs from mail server
SIEM Query:
source="pineapp" AND (uri="*nicUpload.php*" OR file_upload="true")