mirai

2 Articles

This Week In Security: Medical Backdoors, Strings, And Changes At Let’s Encrypt

February 7, 2025 by 12 Comments

There are some interesting questions afoot, with the news that the Contec CMS8000 medical monitoring system has a backdoor. And this isn’t the normal debug port accidentally left in the firmware. The CISA PDF has all the details, and it’s weird. The device firmware attempts to mount an NFS share from an IP address owned by an undisclosed university. If that mount command succeeds, binary files would be copied to the local filesystem and executed.

Additionally, the firmware sends patient and sensor data to this same hard-coded IP address. This backdoor also includes a system call to enable the eth0 network before attempting to access the hardcoded IP address, meaning that simply disabling the Ethernet connection in the device options is not sufficient to prevent the backdoor from triggering. This is a stark reminder that in the firmware world, workarounds and mitigations are often inadequate. For instance, you could set the gateway address to a bogus value, but a slightly more sophisticated firmware could trivially enable a bridge or alias approach, completely bypassing those settings. There is no fix at this time, and the guidance is pretty straightforward — unplug the affected devices.

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White-hat Botnet Infects, Then Secures IoT Devices

April 24, 2017 by 32 Comments

[Symantec] Reports Hajime seems to be a white hat worm that spreads over telnet in order to secure IoT devices instead of actually doing anything malicious.

[Brian Benchoff] wrote a great article about the Hajime Worm just as the story broke when first discovered back in October last year. At the time, it looked like the beginnings of a malicious IoT botnet out to cause some DDoS trouble. In a crazy turn of events, it now seems that the worm is actually securing devices affected by another major IoT botnet, dubbed Mirai, which has been launching DDoS attacks. More recently a new Mirai variant has been launching application-layer attacks since it’s source code was uploaded to a GitHub account and adapted.

Hajime is a much more complex botnet than Mirai as it is controlled through peer-to-peer propagating commands through infected devices, whilst the latter uses hard-coded addresses for the command and control of the botnet. Hajime can also cloak its self better, managing to hide its self from running processes and hide its files from the device.

The author can open a shell script to any infected machine in the network at any time, and the code is modular, so new capabilities can be added on the fly. It is apparent from the code that a fair amount of development time went into designing this worm.

So where is this all going? So far this is beginning to look like a cyber battle of Good vs Evil. Or it’s a turf war between rival cyber-mafias. Only time will tell.