In a technical community, someone recently put together a roundup of newly released industrial devices, and cellular Wi-Fi routers (cellular wifi router) made up a sizable share of the list. For manufacturers planning to buy such devices in volume for deployment, these roundups are worth reading with one extra question in mind: beyond the spec sheet, does the firmware contain any passwords written directly into the code? If hardcoded credentials exist in the firmware, an attacker can obtain access through reverse engineering — and no amount of configuration changes on the device will close that door.
Default passwords and hardcoded credentials often get lumped together, but the risk levels are far apart. A default password is the management password preset at the factory; changing it at first login resolves the issue. Hardcoded credentials are strings compiled into the firmware itself — debug backdoors, vendor maintenance accounts, embedded keys. One simple test tells them apart: change the login password in the management interface, and the default password stops working, while a hardcoded one does not. An administrator can rotate the front-facing password a hundred times; the channel buried in the firmware stays wide open.
An industrial router's firmware image can be extracted for static analysis. String scans plus decompilation leave hardcoded accounts and passwords nowhere to hide in the code. The consequences extend well beyond a single device: every online unit running the same model and the same firmware version shares the same "key." One successful reverse-engineering effort, followed by mass scanning, lets an attacker log into devices one by one — reconfiguring them, exfiltrating data, or turning the routers into beachheads into the internal network.
The remediation cost is just as lopsided. A default password problem ends the moment it is changed; a hardcoded credential requires code changes, recompilation, and a new firmware release, followed by unit-by-unit upgrades across the deployed fleet. A few lines of code left in at the factory end up being paid for by every device in the field.
One more point worth noting: industrial routers rarely sit alone. They are deployed in fleets of dozens or hundreds at remote sites, pumping data from PLCs, cameras, and sensors back to a control center. A fleet-wide credential compromise is not a single-site incident — it is a simultaneous breach of every customer network those routers touch, which is exactly why auditors have started asking about firmware provenance during procurement.
Three checks during the selection phase cost the least and filter out the most:
First, run a password-change retest on arrival. Change the management password, then try logging in again with every preset account listed in the documentation; restore the device to factory settings once and confirm the old password is invalidated. Fifteen minutes of work screens out most obvious problems.
Second, ask the vendor directly: whether debug or maintenance accounts with fixed credentials exist in the firmware, whether they can be disabled, and what the firmware update channel is when a security issue is found. A vendor that answers these questions head-on usually has its firmware management in order.
Third, look at certifications. EN 18031 is the EU's harmonized standard for the cybersecurity of networked devices, introduced under the RED cybersecurity requirements and covering default passwords, authentication mechanisms, and security updates. Passing it means the device has been through third-party review on exactly the clauses that hardcoded-credential incidents violate. Multiple PUSR cellular routers have passed this certification; during selection, pull out the certification list and check it directly.
Set separate passwords for the management interface, the serial console, and the cloud-platform binding, and change all of them. Close every remote access entry that is not needed, and keep management traffic inside a VPN tunnel rather than exposing it to the public internet. Verify and upgrade firmware versions centrally through the remote management platform instead of touching devices one by one, so no unit is left on an old release. Finally, segment the management network from the operational network. With these four actions done, even if residual firmware issues exist, the attack surface shrinks by more than half.
Judged against the standards above, two devices stand out. The USR-G806w is a 4G industrial cellular router built on a Qualcomm solution, offering three Ethernet ports (configurable as 1 WAN + 2 LAN or 3 LAN), Wi-Fi up to 300 Mbps, and the full VPN suite of OpenVPN, IPsec, PPTP, L2TP, and GRE. OpenVPN configurations can be imported in one click from .ovpn files and PKCS#12 certificates — certificate-based authentication in place of static passwords sidesteps the entire hardcoded-credential problem by design, and the router can maintain OpenVPN tunnels to three different servers simultaneously. It works with the PUSR remote management platform for remote configuration, reboot, and firmware upgrades, and offers hardware-plus-software dual watchdogs, surge/EFT and ESD protection, a wide operating range of -20°C to 70°C, and both DIN-rail and wall mounting — the standard profile for unattended cabinets and distributed equipment.
For sites with higher bandwidth demands, the industrial 5G cellular router USR-G816 fits: a Qualcomm quad-core processor with the X62 modem supporting both SA and NSA networks, the same VPN capabilities as the G806w, the ability to act as a client to three different OpenVPN servers simultaneously while also running as an OpenVPN server, a -35°C to 75°C operating range, industrial EMC protection, a hardware watchdog, and a serial port for direct IoT integration — suited to high-bandwidth backhaul and multi-device access sites.
The hardcoded-credential problem can be pressed down to a very low level by onemore question during selection, one more test during acceptance, and four more actions during deployment. When choosing a cellular wifi router, writing "does the firmware contain a password that cannot be changed" into the acceptance checklist is the cheapest security control in the entire chain.
