Moxa NPort 5000 Series Firmware Improper Validation of Integrity Check Vulnerability
Monitor6.5MPSA-233328Oct 20, 2023
Summary
All firmware versions of the Moxa NPort 5000 Series are vulnerable to improper validation of firmware integrity (CVE-2023-4929). Insufficient checks on firmware updates allow an unauthorized attacker with administrative privileges to upload malicious firmware and gain control of the device. The vulnerability stems from weak integrity validation mechanisms that do not properly verify the authenticity and integrity of firmware images before installation.
What this means
What could happen
An attacker with administrative access could upload malicious firmware to the NPort 5000 that passes integrity checks, potentially gaining full control of the device and disrupting serial-to-Ethernet communications to connected industrial equipment.
Who's at risk
Water utilities, electric utilities, and manufacturing facilities using Moxa NPort 5000 Series devices for serial-to-Ethernet communication to legacy PLCs, flow meters, analyzers, or other serial instruments should be concerned. The NPort 5000 is commonly deployed in SCADA and process automation networks.
How it could be exploited
An attacker with administrative credentials accesses the device's firmware update interface (web-based or management tool) and uploads a modified firmware image. Due to insufficient integrity validation, the malicious firmware bypasses security checks and is installed, giving the attacker command execution on the NPort 5000.
Prerequisites
- Administrative (high privilege) credentials for the NPort 5000
- Network access to the device management interface (typically port 21, 80, or 443)
- Ability to craft a firmware image that passes weak integrity checks
remotely exploitableadministrative credentials requiredlow complexity attackno patch availableaffects device management layer
Exploitability
Low exploit probability (EPSS 0.0%)
Affected products (1)
ProductAffected VersionsFix Status
NPort 5000All versionsNo fix (EOL)
Remediation & Mitigation
0/5
Do now
0/2WORKAROUNDRestrict administrative access to the NPort 5000 management interface using firewall rules; allow only trusted engineering workstations and management systems to reach the device
HARDENINGDisable remote firmware update capability if not required; manage updates only from local console or trusted networks
Schedule — requires maintenance window
0/1Patching may require device reboot — plan for process interruption
HARDENINGReview and enforce strong administrative password policies for all NPort 5000 devices
Mitigations - no patch available
0/2NPort 5000 has reached End of Life. The vendor will not release a patch. Apply the following compensating controls:
HARDENINGImplement network segmentation to isolate the NPort 5000 on a restricted management VLAN, separate from general corporate network access
HARDENINGMonitor and log all firmware update attempts; alert on any unauthorized update activities
CVEs (1)
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