Big, bad, scary bug of the moment is CVE-2018-10933.
This is a serious flaw – in fact, it’s a very serious flaw – in a free software library called libssh.
The flaw is more than just serious – it’s scary, because it theoretically allows anyone to log into a server protected with libssh without entering a password at all.
Almost all Unix and Linux servers use SSH for remote administration, and there are an awful lot of awfully large server farms out there, and so there’s an awful lot of SSH about.
SSH stands for secure shell, where the term shell is Unix-speak for a command prompt, the place where most Unix-style system administration functions are performed, whether manually by a logged-in human, or automatically via a logged-in script.
But SSH is used for much more than just shell logins because it creates what’s often called a secure tunnel – a general-purpose encrypted data channel between two computers on the internet.
Notable uses for SSH include secure file transfer between servers, and secure data synchronisation between data centres.