chicksdaddy writes from a report via The Security Ledger: The Mirai malware that is behind massive denial of service attacks involving hundreds of thousands of "Internet of Things" devices may also affect cellular modems that connect those devices to the internet, the Department of Homeland Security (DHS) is warning. An alert issued by DHS's Industrial Control System CERT on Wednesday warned that cellular gateways manufactured by Sierra Wireless are vulnerable to compromise by the Mirai malware. While the routers are not actively being targeted by the malware, "unchanged default factory credentials, which are publicly available, could allow the devices to be compromised," ICS-CERT warned. The alert comes after a number of reports identified devices infected with the Mirai malware as the source of massive denial of service attacks against media websites like Krebs on Security and the French hosting company OVH. The attacks emanated from a global network of hundreds of thousands of infected IP-enabled closed circuit video cameras, digital video recorders (DVRs), network video recorders (NVRs) and other devices. Analysis by the firm Imperva found that Mirai is purpose-built to infect Internet of Things devices and enlist them in distributed denial of service (DDoS) attacks. The malware searches broadly for insecure or weakly secured IoT devices that can be remotely accessed and broken into with easily guessed (factory default) usernames and passwords. The report adds: "Sierra said in an alert that the company has 'confirmed reports of the 'Mirai' malware infecting AirLink gateways that are using the default ACEmanager password and are reachable from the public internet.' Sierra Wireless LS300, GX400, GX/ES440, GX/ES450, and RV50 were identified in the bulletin as vulnerable to compromise by Mirai. Furthermore, devices attached to he gateway's local area network may also be vulnerable to infection by the Mirai malware, ICS-CERT warned. Sierra Wireless asked affected users to reboot their gateway. Mirai is memory resident malware, meaning that is erased upon reboot. Furthermore, administrators were advised to change the password to the management interface by logging in locally, or remotely to a vulnerable device."