Basically what's happened here is that Telecom Malaysia told one of Level3's networks (AS3549 - Global Crossing) that it was capable of delivering traffic to... anywhere on the Internet. Global Crossing apparently didn't have the usual sanity checks in place.
Because of how BGP works, once GBLX decided the route seemed reasonable, it immediately proceeded to dump huge amounts of traffic on the tiny Telecom Malaysia. This isn't incorrect behavior on GLBX's part (accepting the routes was incorrect, but sending the traffic was correct once they were accepted). This is way more traffic than Telecom Malaysia was prepared to handle.
Every tier 1 network gets rid of traffic as soon as possible (because it reduces their costs), completely ignoring performance or whether a route seems sensible. Telecom Malaysia therefore claimed to the most attractive route from anywhere near Malaysia to most of the world.
Level3 is one of the biggest telecoms in the world -- and in fact the biggest by far in that region. This means that most of the Internet probably stopped working for anyone anywhere near Malaysia.