CVE-2021-39289
📋 TL;DR
This vulnerability affects NetModule networking devices where passwords are stored insecurely using cleartext or reversible encryption. Attackers with access to device configuration files could extract credentials to gain unauthorized access. Affected models include NB800, NB1600, NB1601, NB1800, NB1810, NB2700, NB2710, NB2800, NB2810, NB3700, NB3701, NB3710, NB3711, NB3720, and NB3800 with firmware before specified versions.
💻 Affected Systems
- NB800
- NB1600
- NB1601
- NB1800
- NB1810
- NB2700
- NB2710
- NB2800
- NB2810
- NB3700
- NB3701
- NB3710
- NB3711
- NB3720
- NB3800
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to network infiltration, credential theft, data exfiltration, and potential lateral movement to other systems.
Likely Case
Unauthorized administrative access to affected NetModule devices, allowing configuration changes, traffic interception, or device disruption.
If Mitigated
Limited impact if devices are isolated, have strong network controls, and attackers cannot access configuration files.
🎯 Exploit Status
Exploitation requires access to device configuration files, which may be obtained through other vulnerabilities or physical access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.3.0.113, 4.4.0.111, or 4.5.0.105 and later
Vendor Advisory: https://www.netmodule.com
Restart Required: Yes
Instructions:
1. Download latest firmware from NetModule support portal. 2. Backup current configuration. 3. Upload and install firmware update via web interface or CLI. 4. Reboot device. 5. Verify firmware version.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected devices to restricted network segments to limit attack surface.
Access Control Hardening
allImplement strict firewall rules to limit administrative access to trusted IPs only.
🧯 If You Can't Patch
- Change all passwords to complex, unique credentials and monitor for unauthorized access.
- Disable remote management interfaces and require physical access for configuration changes.
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface (System > Status) or CLI command 'show version'.Check Version:
show versionVerify Fix Applied:
Confirm firmware version is 4.3.0.113, 4.4.0.111, 4.5.0.105 or later.📡 Detection & Monitoring
Log Indicators:
- Failed login attempts from unexpected sources
- Configuration file access/modification events
- Unauthorized administrative sessions
Network Indicators:
- Unexpected administrative connections to device management ports
- Traffic patterns indicating configuration changes
SIEM Query:
source="netmodule_device" AND (event_type="config_access" OR event_type="failed_login")