On BashLite and Shellshock

A number of people have been in touch with me about the fact that our Linux courses use an embedded target system that deploys BusyBox as standard and that there’s a “known exploit” doing the rounds called BashLite.SMB – this is obviously a cause for alarm!… Right?

WRONG!! Never one to shy away from defending my beloved Linux I wanted to make a quick public service announcement to say that this appears to be a fairly run-of-the-mill piece of malware riding on the coat tails of the significantly more dangerous ShellShock vulnerability which should be patched!

Busybox itself was never vulnerable to the Shellshock exploit due to it’s usage of an alternative shell – ash – which isn’t a bug-for-bug implementation of Bash.
BashLite is a backdoor opening, information stealing tool that can also be used as part of Command & Control based attacks and is typically the second prong of an attack that has already granted access to the system – either by ShellShock itself (you’re not running unpatched Bash on your device are you?) or by administrators and/or implementers deploying backdoored scanners to check their devices for ShellShock.

My advice is to keep devices off of the Internet during development, make sure they’re clean, keep your dev machines up-to-date with the latest patches, don’t ship devices that rely on components that have a history of bugs (and don’t expose said component via the web!), design and utilise an update strategy – preferably one that can be automated – and don’t trust everything you read on the internet!

If you’re really concerned about security and the types of attacks faced by embedded Linux users and how they work then I heartily recommend our new Secure Linux Programming course.



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About Niall Cooling

Co-Founder and Director of Feabhas since 1995. Niall has been designing and programming embedded systems for over 30 years. He has worked in different sectors, including aerospace, telecomms, government and banking. His current interest lie in IoT Security and Agile for Embedded Systems.
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