Check and update broken links

[fguisso]

Motivation

There are a lot of links inside SecDevLabs and everyone needs to work correctly with new users to follow the right directions.

It would be great if

Update broken links and add missing fix-mitigation PR's links.

What we expect

All normal links and the fix-mitigation PR's links works.

[ihmorais]

hi! can i work on this issue? and sorry for the dumb question but: i didnt understand the second instruction. what is a "missing fix-mitigation PR's links."?

[fguisso]

There are no dump questions @ihmorais. You can work on this issue, there's no need to fix all links, you can open a PR's resolve some links and anyone else can continue your work.

Just one rule, don't open PR with fix just one link, this way we will mark your PR with SPAM tag.

About fix-mitigation, if you open an exercise in the bottom text you will find the fix-mitigation link point to solved exercises. Not every exercise have a fix-mitigation link. e.g. A1 - TicTacToy