Or during, and with open source it could have been possible for independent fixes to have been created as people figured out through trial and error. Additionally, something like this would have cost Crowdstrike a ton of trust, and we would see forks of their code to prevent this from happening again, and now have multiple options. As it stands, we have nothing but promises that something like this won’t happen again, and no control over it without abandoning the entire product.
Even if a fix was discovered quickly it wouldn’t prevent the problem that it must be manually fixed on each computer. In this case a fix was discovered quickly even without access to source code.
Just having more eyes on the source code won’t do much. To discover errors like these the program must be properly tested on actual devices. This part obviously went wrong on Crowdstrike’s side. Making the code open source won’t necessarily fix this. People aren’t going to voluntarily try every cutting edge patch on their devices before it goes live.
I also doubt any of the forks would get much traction. IT departments aren’t going to jump to the next random fork, especially when the code has kernel access. If we can’t trust Crowdstrike, how can we trust new randos?
