CVE-2024-9138: Moxa Router Privilege Escalation Vulnerability

CVE-2024-9138 Overview

CVE-2024-9138 is a hard-coded credentials vulnerability affecting Moxa cellular routers, secure routers, and network security appliances. An authenticated user can leverage embedded credentials to escalate privileges and obtain root-level access to the underlying operating system. Root access on these devices exposes the network perimeter, allowing an attacker to modify routing, inspect traffic, and pivot into segmented industrial environments. The weakness is categorized under CWE-656: Reliance on Security Through Obscurity, reflecting the presence of secret values inside firmware.

Critical Impact
Authenticated attackers can escalate to root and gain full control of affected Moxa networking devices, undermining perimeter and segmentation controls.

Affected Products

Moxa cellular routers
Moxa secure routers
Moxa network security appliances

Discovery Timeline

2025-01-03 - CVE-2024-9138 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-9138

Vulnerability Analysis

The vulnerability stems from static, hard-coded credentials embedded in the firmware of affected Moxa networking devices. An attacker who already holds a valid low-privilege account on the device can present these credentials to a privileged interface and obtain root shell access. Because the credentials are baked into the firmware image, they cannot be revoked by a customer without a vendor-supplied update.

Once root is achieved, the attacker controls every network function of the device. This includes packet capture, firewall rule modification, VPN configuration, and persistence via startup scripts. In operational technology (OT) deployments, such control may allow lateral movement into segmented process control networks.

The attack vector is Network, and privileges required are High, meaning the attacker must first authenticate. Impact to confidentiality, integrity, and availability of the vulnerable device is High. The EPSS probability is 1.145% at the 64.291 percentile.

Root Cause

The root cause is the inclusion of static credentials in shipped firmware, mapped to CWE-656. The design assumes that keeping the credentials undisclosed provides security. Once the values are recovered from a firmware image or leaked, every device sharing that firmware becomes exploitable.

Attack Vector

Exploitation requires network reachability to the device management interface and a valid authenticated session. The attacker submits the hard-coded credentials to a privileged service, and the device grants root access. No user interaction is required. See the Moxa Security Advisory MPSA-241155 for the vendor-confirmed exploitation path.

No public proof-of-concept exploit is currently available, and the CVE is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2024-9138

Indicators of Compromise

Unexpected root-level shell sessions or interactive logins on Moxa routers and security appliances.
Configuration changes, firewall rule modifications, or new VPN tunnels that do not map to authorized change tickets.
New scheduled tasks, startup scripts, or persistent processes on device firmware.

Detection Strategies

Compare running configurations against known-good baselines to identify unauthorized modifications on Moxa devices.
Alert on authentication events that transition a low-privilege account directly to root context.
Ingest device syslog into a centralized platform and correlate management-plane logins with source IP reputation and change windows.

Monitoring Recommendations

Restrict management interfaces to dedicated administrative VLANs and monitor for access attempts from unauthorized networks.
Continuously monitor firmware versions across the Moxa fleet to confirm patched releases are deployed.
Log and review all administrative sessions, including command history where supported by the device.

How to Mitigate CVE-2024-9138

Immediate Actions Required

Inventory all Moxa cellular routers, secure routers, and network security appliances and identify firmware versions in production.
Apply the firmware updates referenced in the Moxa Security Advisory MPSA-241155.
Rotate all administrative credentials on affected devices after patching.
Audit historical authentication and configuration change logs for signs of prior abuse.

Patch Information

Moxa has published fixed firmware versions for affected product families. Refer directly to the Moxa Security Advisory MPSA-241155 for the current fixed versions matched to each model and for guidance on staged deployment in operational technology environments.

Workarounds

Block management interface access from untrusted networks using upstream firewall ACLs.
Place device management on an out-of-band network segment reachable only through a jump host.
Disable unused services and remote management protocols on the device until patching is complete.
Enforce strong, unique administrative account credentials and remove any unnecessary local accounts.

bash

# Example: restrict Moxa device management to an admin subnet at the upstream firewall
# Replace 10.0.0.0/24 with your administrative management network
iptables -A FORWARD -p tcp -d <moxa_device_ip> --dport 443 -s 10.0.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <moxa_device_ip> --dport 443 -j DROP
iptables -A FORWARD -p tcp -d <moxa_device_ip> --dport 22 -s 10.0.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <moxa_device_ip> --dport 22 -j DROP