Normally updates like this are patched quietly, and sometimes without disclosing what exactly the exploit is

This one was leaked early and tutorials supposedly popped up on Twitter, all before the patches were released to relevant software

On top of that, it was a pretty bad exploit (RCE)

So websites were taken offline because either

• they needed to wait for someone with experience to confirm it was patched and safe
• they needed to wait for an update to be sent their way

There’s a vulnerability in php that allows malicious actors to execute code on your server. Everyone is advised to take their php website down until the moment they have implemented php’s security patch. If they leave the vulnerable site up, consequences could be severe, all user data could be stolen.

This was mostly advice from before the patches were available. With no real mitigation or remedy and no patches available, most people opted to simply disconnect the whole thing from the internet, rather than leave a vulnerable system online. The installation of the patches themselves should be very quick and require none to minimal downtime.

The US National Security Agency told all organisations using PHP to take their systems offline if they were unable to patch them immediately.

It can take awhile to patch every system in the world that uses PHP at the same time, so until then it’s better to just turn the server off until you can.