CVE-2020-12842
📋 TL;DR
CVE-2020-12842 is a critical privilege escalation vulnerability in iSmartgate PRO garage door controller software. Attackers can append arbitrary PHP code to a specific cron file, potentially gaining root access to the system. This affects all users running iSmartgate PRO version 1.5.9.
💻 Affected Systems
- iSmartgate PRO
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root-level access, allowing attackers to control garage doors, access home networks, install persistent backdoors, and pivot to other connected devices.
Likely Case
Unauthorized garage door operation, surveillance of garage activity, and potential access to connected home automation systems.
If Mitigated
Limited to garage door control disruption if system is isolated from other networks and access controls are in place.
🎯 Exploit Status
Exploitation requires simple HTTP requests to append PHP code to the vulnerable cron file. No authentication is needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 1.5.9
Vendor Advisory: https://ismartgate.com/secure-garage-door/
Restart Required: Yes
Instructions:
1. Log into iSmartgate admin interface. 2. Check for firmware updates. 3. Apply the latest firmware update. 4. Reboot the device. 5. Verify the update was successful.
🔧 Temporary Workarounds
Remove file write permissions
linuxRemove write permissions from the vulnerable PHP file to prevent code injection
chmod 444 /cron/checkUserExpirationDate.php
Network isolation
allIsolate iSmartgate device from internet and restrict local network access
🧯 If You Can't Patch
- Disconnect device from internet and place on isolated VLAN
- Implement strict firewall rules to only allow necessary traffic to/from the device
🔍 How to Verify
Check if Vulnerable:
Check if /cron/checkUserExpirationDate.php exists and is writable by web server user. Also check firmware version.Check Version:
Check admin interface or SSH into device and check firmware version in system settingsVerify Fix Applied:
Verify firmware version is newer than 1.5.9 and test that PHP code cannot be appended to the vulnerable file.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /cron/checkUserExpirationDate.php
- File modification timestamps on the vulnerable PHP file
- Unexpected PHP processes running
Network Indicators:
- HTTP traffic to port 80/443 containing PHP code in POST data
- Unusual outbound connections from iSmartgate device
SIEM Query:
source="iSmartgate" AND (uri="/cron/checkUserExpirationDate.php" OR file_modification="/cron/checkUserExpirationDate.php")