CVE-2021-46902
📋 TL;DR
This vulnerability in Meinberg LANTIME-Firmware's LTOS-Web-Interface allows authenticated admin users to bypass path validation controls, enabling unauthorized reading or deletion of files. It affects systems running LANTIME-Firmware versions before 6.24.029 MBGID-9343 and 7.x before 7.04.008 MBGID-6303. The issue stems from improper path validation (CWE-22) in the web interface.
💻 Affected Systems
- Meinberg LANTIME-Firmware
📦 What is this software?
Lantime Firmware by Meinbergglobal
Lantime Firmware by Meinbergglobal
⚠️ Risk & Real-World Impact
Worst Case
Admin users could read sensitive system files (including credentials, configuration data) or delete critical system files, potentially causing service disruption, data loss, or enabling further privilege escalation.
Likely Case
Authorized but malicious admin users could access files outside their intended scope, potentially exposing sensitive information or modifying system configurations.
If Mitigated
With proper access controls and monitoring, impact is limited to authorized admin users who already have significant system access, though they could still exceed intended permissions.
🎯 Exploit Status
Exploitation requires admin credentials. No public exploit code has been identified, but the vulnerability description suggests simple path manipulation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.24.029 MBGID-9343 or 7.04.008 MBGID-6303
Vendor Advisory: https://www.meinberg.de/german/news/meinberg-security-advisory-mbgsa-2021-03-meinberg-lantime-firmware-v7-04-008-und-v6-24-029.htm
Restart Required: Yes
Instructions:
1. Download the appropriate firmware update from Meinberg support portal. 2. Backup current configuration. 3. Apply firmware update following vendor instructions. 4. Reboot the device. 5. Verify the update was successful.
🔧 Temporary Workarounds
Restrict Admin Access
allLimit admin account access to only trusted personnel and implement strong authentication controls.
Network Segmentation
allRestrict network access to the LTOS-Web-Interface to only necessary management networks.
🧯 If You Can't Patch
- Implement strict access controls for admin accounts and monitor admin activity closely
- Consider disabling the web interface if not required and use alternative management methods
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface or SSH: System > About or using 'show version' command. Compare against affected versions.Check Version:
Via SSH: 'show version' or check web interface at System > AboutVerify Fix Applied:
Verify firmware version is 6.24.029 MBGID-9343 or higher for v6, or 7.04.008 MBGID-6303 or higher for v7.📡 Detection & Monitoring
Log Indicators:
- Unusual file access patterns by admin users
- File deletion events in system logs
- Web interface access to unexpected file paths
Network Indicators:
- HTTP requests to web interface with unusual file path parameters
- Admin authentication from unexpected sources
SIEM Query:
source="lantime-logs" AND (event="file_access" OR event="file_delete") AND user="admin" AND path NOT CONTAINS "/expected/path/"