Samsung overstepped the boundaries of marketing when they were caught paying students in Taiwan to go on message boards to bash HTC, and falsely report that HTC's phones were crashing. That's a big no-no, if you couldn't already tell.
Of course, companies have indirectly bashed their competition in different ways. Take Tim Cook's jab at Microsoft during the iPad Air announcement:
“Our competition is different: They’re confused. They chased after netbooks. Now they’re trying to make PCs into tablets and tablets into PCs. Who knows what they’ll do next? I can’t answer that question, but I can tell you that we’re focused.”
Tim Cook just threw every one of his competitors under the bus with that line, but, as everyone who watched the announcement can attest to, it was apparent that Microsoft was back in Apple's crosshairs. Okay, so there's that. Yet, some companies choose to directly attack their competition. Take Samsung. Though Samsung's biggest competition is Apple, HTC is close to being next in line. So, when Taiwan's Fair Trade Commission responded to reports that Samsung had hired a large number of writers and employees to "highlight the shortcomings of competing products" on message forums, it wasn't a surprise that all of those products just happened to be from HTC. The hired employees, many of whom were students, wrote negative reviews about HTC products and reported that phones were crashing. Samsung admitted the allegations were true, and have now been slapped with the equivalent of a $340,000 fine.
Sadly, this fine won't make HTC's phones any better.