No, not all of the major sites are always safe because some of these major sites have flaws and loopholes which no one can find yet. If any hacker finds them, then they might be able to manipulate the data on that major site and even steal all their stored data from them easily. This is why every website, either major or minor, should consider performing several verifications on their website to find and fix any kind of flaws. You can also lookup some verification techniques for 메이저사이트 on the internet.