Can somebody explain these ransomwear attacks?

Sun Jun 27 05:49:11 UTC 2021

Finding vulnerabilities and how to exploit them to run malware
in closed source code is nigh on impossible. 
Anyone can read open source code.

What is possible is to analyze patches to figure out what was fixed
and then to attack those that didn't apply the patches.

Even easier is old releases. Patches often have more than one fix,
but a patch for an old release is almost guaranteed to be a fix
for a single vulnerability. That makes it easier to analyze.

Regards,
Jakob.