Legacy Tech, Modern Threats: Serial-to-IP Converter Bugs Put Hospitals and Industry at Risk

In the heart of a bustling hospital, a patient monitor suddenly loses connection. In a remote power substation, sensor readings mysteriously change. These aren’t scenes from a cyber-thriller - they’re real-world risks brought to light by a recent investigation into serial-to-IP converters, devices that quietly bridge the gap between old and new technologies in critical infrastructure. Now, a cache of newly discovered vulnerabilities threatens to turn these unsung workhorses into prime targets for cyberattacks.

Serial-to-IP converters - also known as serial device servers - are the invisible glue holding together much of the world’s operational technology (OT). They allow decades-old industrial controllers and medical equipment to communicate over modern Ethernet networks. But according to Forescout Technologies, these devices are riddled with vulnerabilities that could be exploited for sabotage, espionage, or extortion.

Major manufacturers like Moxa, Digi, Advantech, Perle, Lantronix, and Silex have shipped millions of these converters, which are found everywhere from energy grids and water plants to hospitals and transport hubs. A simple internet scan reveals nearly 20,000 devices directly exposed to the world - an open invitation to hackers.

The newly reported flaws, collectively dubbed BRIDGE:BREAK, affect key products from Silex and Lantronix. Forescout’s analysis identified 20 weaknesses, including several that require no login to exploit. Attackers could inject malicious code, upload rogue firmware, or even seize full control of the device. The consequences are chilling: in healthcare settings, attackers could halt lab analyzers, disable surgical lighting, or sever communication with patient monitors, leading to dangerous delays or errors. In industrial sites, they could manipulate sensor data to conceal hazardous conditions or trigger shutdowns.

While both Lantronix and Silex have released security patches, the sheer number of devices and the slow pace of updating in OT environments means many remain vulnerable. Worse, history shows these converters are already in the crosshairs: Russian hackers leveraged similar weaknesses in the infamous 2015 Ukraine energy attack, and recent incidents have targeted energy facilities in Poland.

Security experts warn that organizations must not overlook these “invisible” devices. A single overlooked converter could be the weak link that brings down an entire system. As Forescout prepares to release its full BRIDGE:BREAK report, the message is clear: in the race between defenders and attackers, even the smallest device can tip the balance.

The lesson is stark: as legacy tech and modern networks intertwine, every device - no matter how humble - can become a gateway for cyber threats. Hospitals, utilities, and factories must act now to patch, monitor, and protect these overlooked linchpins before attackers exploit the cracks in our digital foundations.

WIKICROOK

• Serial: Serial is a method of data transmission, often used in older devices, where data is sent bit by bit over a single channel or wire.
• Operational Technology (OT): Operational Technology (OT) includes computer systems that control industrial equipment and processes, often making them more vulnerable than traditional IT systems.
• Remote Code Execution (RCE): Remote Code Execution (RCE) is when an attacker runs their own code on a victim’s system, often leading to full control or compromise of that system.
• Denial: Denial in cybersecurity means making systems or services unavailable to users, often through attacks like Denial-of-Service (DoS) that flood them with traffic.
• Firmware: Firmware is specialized software stored in hardware devices, managing their core operations and security, and enabling them to function properly.